C7 led Christmas lights are the most prevalent of the outdoor led string lights. They are used indoors but with less frequency. Our standard grade C7 led lights are all 16.5 feet long, are 25 lights to a string and have 8 inch spacing. The wattage used by the entire C7 led light string is an infinitesimal 1.7 watts! This is an amazingly small number and represents very significant energy savings. UL standards on our C7 led Christmas lights say we can string together 210 watts which will equal 124 strings connected end to end into one normal outlet. What else is amazing about our C7 led lights is that those 124 strings will only use 2.3 amps. A normal outlet will take 15 amps before blowing a fuse, this means we could conceivably (but not recommended) string together from one outlet over two miles of C7 led Christmas lights all the while saving up to 98% in electricity use.