C7 bulbs and C9 bulbs are easily one of the most recognizable Christmas light bulb available. Their design remains popular because it's a simple, traditional look that people grew up with and instantly recognize as a Christmas light. C7 & C9 bulbs come in a variety of styles, Steady Burning with both Transparent and Painted Bulb colors and Twinkle bulbs that some in Transparent colors. Transparent bulbs are dipped in colors multiple times to give a rich, deep color that will last for multiple seasons. Painted (or Opaque) bulbs have bright colors that usually give off a softer glow than their transparent counterparts.

C7 bulbs are usually 5 watts, these candelabra base bulbs are small enough to decorate your Christmas tree in your living room but just big enough to line the outside of your home. You can usually run approximately 100 bulbs in one continuous run of light line. C7 stringers and spools of wire come in a variety of colors and spacings. Spacings usually range from 6 being the smallest to 24 being the longest. 12" Spacing is the most common for outdoor applications. Wire comes in Green and White colors and 2 different wire styles. Spt-1 and Spt-2 are the two different wires that are most common, Spt-1 handles 7 amps and Spt-2 handles 10 amps. What does this mean? Well Spt-2 has thicker insulation and lets you run more bulbs or brighter bulbs off the same wire.

C9 bulbs are generally 7 watts and follows most of the same principles as a C7. The wire comes in even wider spacings, 36 being the widest for C9. You can get wire black in color for C9 bulbs, this may be because they are usually used for larger lighting application since they are a larger bulbs. Commercial buildings and large displays are usually lit with C9, not because they are better, they are just a little bigger and at a distance look better.

There are higher wattage offering for these types of Christmas bulbs, the C7 comes in a 7 watt and the C9 comes in a 10 watt option. They give you a little bit more brightness, but pull more power and we recommend you use Spt-2 Wire for these types of bulb. Now if power is a concern we encourage you to go with the screw in retro fit LED bulbs, these bulbs come in both styles and use only .96 watts of power...less than one whole watt of power! You can run many many more LED screw in bulbs on a continuous string and not have to worry about them burning out or being broken. Check out our Retro Fit LED page for more info.