These set of 2 - 100 ct professional series with white wire is a wonderful light set. Its features include longer length, socket lock and, if one bulb goes out, the others stay lit. The beautiful mucti colored mini bulbs on white wire create an elegant effect. Each strand is 21 ft long, including a 12" lead cord, 2.5" spacing between bulbs, and a 3" end cord. Perfect for indoor/outdoor, UL listed.