What Comes in a Commercial C7 or C9 Light Set?
Every set arrives with the correct number of bulbs to match the pre-sized stringer's length and spacing, removing any guesswork. Bulb color, wire color, and spacing are designed together, giving you a finished, coordinated look straight out of the box. Setup is tool-free, just screw in the bulbs and the set is ready to install.
The bulbs and stringer in every set are the same components as sold separately, so you get the same quality either way. Bulbs are interchangeable, so you can change colors or replace bulbs without buying a whole new set.
Choosing C7 or C9 for a Commercial Display
The C9 is the larger cone-shaped bulb at 3 inches tall from base-to-tip — 50% taller than the C7 so it stands out from a greater distance. On a commercial display that is often the deciding factor, and it is why C9 is the common choice for rooflines and large Christmas trees. 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, along entrances and walkways.
The two sizes take different sockets. C9 bulbs use an E17 intermediate screw base and C7 bulbs use an E12 candelabra screw base, so every stringer is built for the bulb it carries. Because each set arrives with its bulbs already matched, you don't have to worry about matching your bulb size to your stringer unless you buy replacement bulbs later.
OptiCore® and FlexFilament® Bulbs
OptiCore® bulbs are molded from polycarbonate, which is 200 times stronger than glass, with a lens twice as thick as a standard grade LED Christmas bulb for shatterproof durability. An IP67 rating seals every bulb against dust and water, which means winter weather never reaches the diode. A reflective core spreads light evenly through the polycarbonate lens for rich, saturated color with fewer hot spots.
At 0.8 watts per bulb, OptiCore® draws 90% less energy than the 7-watt C9 incandescent it replaces, and bulbs rated for 60,000 hours mean you will change your design long before you change a bulb. OptiCore® is the professional-grade bulb the pros use, built for commercial displays and for anyone who wants a professional result at home. It comes in 10 color options including a 3000K warm white, carries a three-year warranty, and OptiCore® commercial string light sets are UL Certified for the highest standard in safety to give you peace of mind.
FlexFilament® sets take the vintage route. A curved LED filament glows through the lens like an antique Edison bulb, giving your display old-world character with modern LED efficiency, and a transparent lens leaves the filament in full view. The bulbs are lightweight PolyFlex PET, worry-free and shatterproof, rated for 20,000 hours, in eight colors across warm vintage tones and true Christmas color. FlexFilament® bulbs are ETL Certified, on stringers built with UL Recognized Components for safety and peace of mind.
Faceted and Smooth Finishes
OptiCore® bulbs come in diamond-faceted and traditional smooth opaque finishes, allowing you to match the bulb to the look you are building. The faceted lens refracts light into a cut-crystal sparkle that carries from a distance, which is why it is a favorite on rooflines and outdoor displays. The smooth opaque lens diffuses light into a soft, uniform glow like a traditional ceramic or frosted bulb, the softer choice where a display is viewed up close. Steady and twinkle versions come in the same finishes, so you can add movement without changing the look of the bulb. Both finishes use the same shatterproof OptiCore® bulb, so the choice is purely about the look you want.
Wire Color and Themed Sets
OptiCore® sets come in green, white and black wire, so the wire matches the surface it mounts on and blends in during daylight. Green is the usual choice against foliage and darker rooflines, and it is the only wire color FlexFilament® sets come in. White disappears against white gutters, trim and railings, and canopies for weddings and events. Halloween sets pair amber, purple and/or green bulbs on black wire, so the display looks deliberate by day and lit up at night.
The Stringer Inside Every Set
Every set is built on heavy duty 18-gauge commercial-grade wire, which supports more end-to-end connections so you can safely run longer lines of light. A male and female plug on every pre-sized stringer can connect one string to the next, so a single outlet can carry the whole line of light. Pre-sized stringers carry a fused plug that caps the load at 960 watts, which at 12-inch socket spacing is 1,200 feet of lights connected end to end.
The sockets are parallel wired, so if one socket goes out the rest stay lit, and weep holes in every socket let water drain out, keeping rain and melting snow clear of the bulb seat. Every set is rated for indoor and outdoor use, so one set works anywhere you hang it.
Pro Tip:
Pro Tip: Thanks to energy-efficient LED bulbs, with a little planning you can light your entire display from a single outlet. First, calculate the total length you want to light, then order kit lengths that add up to it. Sets are pre-sized, so for 75 feet of roofline, order a 50-foot and a 25-foot set. Start your first set as close as possible to the outlet you plan to use. The male and female plugs on these sets let you connect them together end to end, up to the 960 watts a stringer's fused plug allows, which is 1,200 feet of lights at 12-inch spacing.
C7 & C9 Lens Types & Finishes
C7 & C9 Christmas light bulbs will have either a traditional glass or a durable acrylic lens. Incandescent bulbs always have a glass lens and are generally either transparent or painted with an opaque finish, whereas LED bulbs are available in glass or acrylic with several finishes.
Transparent - A classic choice for Christmas lighting. Transparent light bulbs can have either a glass or acrylic lens, display beautifully in almost any space and go well with any color combination, making this finish one of the most popular of all!
Smooth Opaque Glass - Bold colors, perfect for an outdoor party or colorful Christmas light display. Mix and match opaque bulb colors to create unique lighting themes or hang all white smooth-opaque finish incandescent or LED lights and let your existing decor shine.
Smooth Opaque Acrylic - Smooth opaque acrylic LED bulbs are more durable than glass, shatter-resistant, and ideal for outdoor use. Their even, vibrant glow works well for bold holiday displays or classic white lighting themes. Built to withstand the elements, these bulbs offer long-lasting reliability for any lighting project.
Faceted - The faceted design of our C7 & C9 LED light bulbs reflects a stunning light pattern when hung next to solid surfaces and is very popular in Christmas light displays. Faceted bulbs are made out of a durable acrylic which provides longer life and worry free installation.
Frequently Asked Questions:
Are C7 or C9 better for commercial displays? Neither is better in general; the right size depends on viewing distance. The C9 is the larger cone-shaped bulb at 3 inches tall from base to tip, 50% taller than the C7, so it stands out from a greater distance and is the common choice for rooflines and large Christmas trees. The C7 is 2 inches tall, a finer scale that shows well where a display is viewed up close, along entrances and walkways. Many commercial displays use both, with C9 along the eaves for street-side impact and C7 on railings and entryways for closer detail.
What makes these light sets commercial grade? These sets are built on heavy duty 18-gauge commercial-grade wire with a fused plug, and every socket has weep holes that let water drain out. OptiCore® bulbs are molded from polycarbonate, 200 times stronger than glass, sealed to IP67 against dust and water, and rated for 60,000 hours. OptiCore® commercial string light sets are UL Certified; FlexFilament® bulbs are ETL Certified, on stringers built with UL Recognized Components. The bulbs and stringer in every set are the same components as sold separately, so you get the same quality either way.
Can I connect these sets end to end? Yes. A male and female plug on every pre-sized stringer can connect one string to the next, so a single outlet can carry the whole line of light. Heavy duty 18-gauge commercial-grade wire supports more end-to-end connections, and the sockets are parallel wired, so if one socket goes out the rest stay lit.
How long a display can I light from one outlet? Each stringer carries a fused plug that caps the load at 960 watts. OptiCore® and FlexFilament® bulbs both draw 0.8 watts each, so at 12-inch socket spacing that comes to 1,200 bulbs, or 1,200 feet of light connected end to end from a single outlet.
Can these be used outdoors? Yes. C7 and C9 sets are both rated for indoor and outdoor use, so one set works anywhere you hang it. An IP67 rating seals every OptiCore® bulb against dust and water, which means winter weather never reaches the diode, and weep holes in every socket let water drain out, keeping rain and melting snow clear of the bulb seat.
Are the bulbs shatterproof? OptiCore® bulbs are molded from polycarbonate, 200 times stronger than glass, with a lens twice as thick as a standard grade LED Christmas bulb for shatterproof durability. FlexFilament® bulbs use lightweight PolyFlex PET, which is also shatterproof. No glass bulbs are used in these sets.
Can I replace individual bulbs? Yes. Bulbs are interchangeable, so you can change colors or replace bulbs without buying a whole new set. C9 sets take an E17 intermediate screw base and C7 sets take an E12 candelabra screw base, so match the base size when you order replacements.
