Electrical accessories like bulk wire (also called zip cord), zip sockets and zip plugs are the building blocks you can use to create custom stringers to take your Christmas lights display to the next level. Place lights exactly where you want them - and no place else. Make custom runs of for the exact length you need, and lose the spaghetti bowl of extension cords. You're in control with zip plugs and zip wire, so you can have Christmas lights that look not only beautiful, but clean and professional too.
The C9 is the larger cone-shaped bulb at 3 inches tall from base-to-tip — 50% taller than the 2-inch C7 so it stands out from a greater distance. C9 bulbs use an E17 intermediate screw base, so they drop straight into matching C9 socket wire. The C7 is the smaller cone-shaped bulb at 2 inches tall from base-to-tip, a finer scale that shows well where a display is viewed up close. C7 bulbs use an E12 candelabra screw base, so they drop straight into matching C7 socket wire.
C9 lights are the best Christmas lights for large-scale, high-impact displays — rooflines, driveways, large Christmas trees, and outdoor installations that need to look great from the street. C9 has also become a popular alternative to globe patio lights for backyard patio lighting and outdoor events year-round.
C7 lights are the best Christmas lights for tighter spaces and more detailed displays — railings, window and door frames, mantels and small Christmas trees, and homes with less exterior footprint like condos and townhomes.
OptiCore® is Wintergreen Lighting's C9 and C7 LED Christmas light line, engineered in response to customer demand for better color and more durability than typical C9 and C7 bulbs deliver. OptiCore is the professional-grade bulb the pros use because it is built for commercial displays and anyone who wants a professional result at home.
Every OptiCore bulb has a polycarbonate lens. Polycarbonate is 200 times stronger than glass, and OptiCore's lens is twice as thick as a typical Christmas bulb, for shatterproof durability. A reflective core spreads light evenly through the lens for rich, saturated color with fewer hot spots. A single surface-mounted LED fills the reflective core, lighting the lens for a fuller, more even glow in every bulb. An IP67 rating seals every bulb against dust and water, which means winter weather never reaches the diode.
At 0.8 watts per bulb, OptiCore draws 90% less power than the 7-watt C9 incandescent it replaces, cutting what a full display costs to run. Because per-bulb draw is so low, OptiCore string light sets connect over 1,000 feet end-to-end on a single power line. Bulbs are rated for 60,000 hours, which means you will change your design long before you change a bulb, and a three-year warranty covers three full seasons. Nickel-plated bases resist corrosion and connect cleanly, saving you time and hassle every season, and every bulb is dimmable.
OptiCore® bulbs, complete light sets and pathway kits are UL Certified, independently tested for safe use indoors and out. OptiCore comes in both C9 and C7 sizes, in diamond-faceted and traditional smooth opaque finishes, allowing you to match the bulb to the look you are building. Steady and twinkle versions come in the same finishes, so you can add movement without changing the look of the bulb. Ten colors including a 3000K warm white give you the full palette for traditional and modern displays alike. Buy as complete light sets, replacement bulbs, or pre-assembled pathway light kits.
FlexFilament® is Wintergreen Lighting's vintage Edison-style LED C9 and C7 Christmas light line, created to bring the look of antique filament bulbs into modern LED. A curved LED filament glows through the lens like an antique Edison bulb, giving your display old-world character with modern LED efficiency.
A transparent lens leaves the curved filament in full view, which makes these bulbs a natural fit for patios, porches and anywhere guests stand close. The filament lights along its full curve rather than from a single point, resulting in the even glow of vintage bulbs in a long-lasting LED. Lightweight PolyFlex PET makes for worry-free, shatterproof bulbs, with select products available with a satin glass lens. That softens the filament into an even, candle-like glow, creating an elegant look whether the bulbs are lit or not.
Each bulb draws 0.8 watts, and because per-bulb draw is so low, FlexFilament string light sets connect over 1,000 feet end-to-end on a single power line. Bulbs are rated for 20,000 hours, which means years of use from a single set. FlexFilament bulbs and kits are rated for outdoor use in wet locations, so they hold up through rain, snow and freezing weather.
FlexFilament comes in both C9 and C7 sizes. Eight colors give you range across warm vintage tones and true Christmas color. Buy as complete light sets, replacement bulbs, or pathway kits.
Premium-grade prelamped C9 and C7 LED Christmas light sets are Wintergreen Lighting's ready-to-hang line for outdoor decorating — engineered for reliable construction at a price below the professional-grade tier. These are the best Christmas lights for residential outdoor displays on a budget.
Each bulb has one-piece sealed bulb-and-base construction, so water can't enter the bulb or corrode the socket joint. Shatter-resistant acrylic lenses hold up in outdoor use, and every set is rated for outdoor weather. Sets are UL Certified and Energy Star certified. Bulbs are spaced 8 inches apart — closer than the 12-inch spacing on most outdoor Christmas light sets. Each bulb draws just 0.096 watts, a low per-bulb draw that keeps total power use minimal on long light strings.
Premium-grade prelamped is available in both C9 and C7 sizes, on green wire, in warm white, cool white, and a range of solid colors and themed multicolor combinations. Sold as complete light sets — bulbs are already installed on the string.
Socket wire comes with bare sockets and you add the bulbs you choose (sold separately) and swap them later without replacing the whole string. Choose pre-sized stringers for a ready-to-hang length or bulk spools that can be custom cut so the string fits the project. A stringer arrives with the plugs already attached and ready to hang; spools ship as continuous wire with no plugs, so you cut to the exact length your project needs.
Pre-sized stringers come in lengths from 10 to 119 feet and bulk spools in 500 and 1,000 feet, covering anything from a single porch to a commercial property. Choose your socket spacing from 6 to 24 inches, so you control how full the line of light looks — tight for a dense glow up close, or wider to cover a long roofline and stretch your budget; spacing is offered at 6, 12, 15, 18 and 24 inches. Wire is available in green, white, black and brown, so it matches the surface it mounts on and blends in during daylight.
Heavy-duty 18-gauge commercial-grade wire reduces voltage drop so you can run longer light strings from a single power source. Strings come in SPT1 or SPT2 wire, with SPT2 carrying thicker insulation for harsher weather and SPT1 handling most Christmas light displays. Each stringer can handle up to 960 watts, which is more than 1,000 LED bulbs. A male and female plug on every stringer can connect one string to the next, so a single outlet can carry the whole line of light.
Professional sockets feature weep holes for trouble-free performance through rain and snow, and stringers are rated for indoor and outdoor use, so one string works anywhere you install it. Built with UL Recognized Components for safety and peace of mind. E17 intermediate sockets accept C9 and many G-globe bulbs, so the same string can be used at Christmas and again during patio season.
Pair a stringer or spool with C7 or C9 replacement bulbs, LED or incandescent, to build a complete light string. For custom displays, zip plugs and bulk wire (also known as zip cord) let you place power taps exactly where you need them.
Zip plugs and bulk wire let you build C7 and C9 Christmas light strings of any length, in any configuration, exactly where you need power. Bulk wire (also called zip cord) is UL-listed 18-gauge electrical wire sold on the reel — no sockets, no plugs. Zip plugs are the connectors that clamp onto the wire to make power taps or custom-length stringer segments.
Bulk wire comes in 100- to 1,000-foot lengths, in green, white, black, or brown, and in SPT1 or SPT2 insulation. Zip plugs are sold separately in the same SPT1 and SPT2 insulation grades — match plugs to wire (e.g., SPT1 plugs with SPT1 wire) so the plugs close correctly.
Christmas light clips and hangers let you mount C9 and C7 Christmas lights on gutters, shingles, and roofs, or stake them into the ground for pathway installations. Clips vary by surface and installation angle, so choose the type that matches where your lights are going.
One of the most versatile options is the All-In-One clip, which lets bulbs face multiple directions and works on both shingles and gutters.
Frequently Asked Questions:
What is the difference between C7 and C9 Christmas lights? The C9 is the larger cone-shaped bulb at 3 inches tall from base-to-tip, 50% taller than the 2-inch C7, so it stands out from a greater distance — the reason C9 is the usual pick for rooflines and driveways. The C7 is a finer scale that shows well where a display is viewed up close, on railings, mantels and window frames. C9 bulbs use an E17 intermediate screw base and C7 bulbs an E12 candelabra screw base, so the two are not interchangeable in the same socket.
What does C9 mean on Christmas lights? C9 is a Christmas light bulb shape and size designation: a cone- or candle-shaped bulb (the "C") that's approximately 1.5 inches in diameter and 3 inches tall, with an E17 intermediate screw base.
What is a C7 light bulb? A C7 light bulb is a small cone- or candle-shaped Christmas light bulb, approximately 1.25 inches in diameter and 2 inches tall, with an E12 candelabra screw base. Available in both incandescent and LED, in many colors and finishes. Used on small Christmas trees, mantels, condos and townhomes, small home exteriors, and detail work like window outlines.
Are LED C9 lights worth the higher price? Yes for most buyers. An LED bulb draws under a watt, 90% less than the 7-watt C9 incandescent it replaces, so you can safely run longer lines of light, and LEDs stay cool to the touch. LED bulbs are rated from 20,000 to 60,000 hours with no filament to burn out, against an average life of 3,000 hours for an incandescent bulb. Incandescent still earns its place: it produces the classic glow of a traditional Christmas at the lowest initial cost per bulb. The same comparison applies to C7 bulbs.
How long do LED C9 Christmas lights last? LED C9 bulbs are rated from 20,000 to 60,000 hours with no filament to burn out — OptiCore bulbs at 60,000 hours, FlexFilament at 20,000 — compared with an average life of 3,000 hours for an incandescent C9, which lights six seasons of nightly use. C7 LED bulbs carry the same ratings.
Can I cut a C9 spool to length? Yes. Spools ship as continuous wire with no plugs, so you cut to the exact length your project needs, then cap each end with a zip plug matched to the wire insulation (SPT1 plug for SPT1 wire, SPT2 plug for SPT2 wire), or an outdoor-rated end cap or sealant. The same approach works for C7 spools. Pre-sized stringers are a different product — they arrive with the plugs already attached.
How do I hang C9 or C7 Christmas lights on gutters? Plastic Christmas light clips snap onto the lip of most standard gutters without tools or nails. Slide each clip onto the gutter, then hang each C7 or C9 bulb from a clip. The All-In-One clip works on both shingles and gutters and lets bulbs face multiple directions. Use only outdoor-rated extension cords and stay within the manufacturer's max connection count.
Pro Tip:
Pro Tip: When planning a large light display, remember that end-to-end connectability differs dramatically between professional-grade LED sets and cheaper big box store alternatives. OptiCore and FlexFilament string light sets support over 1,000 feet daisy-chained on a single power line — thanks to a very low 0.8 watt per-bulb draw and heavy-duty 18-gauge commercial-grade stringers. If you're planning a longer display, professional-grade LED gives you far more room to work without adding circuits or extra extension cords.
