This set of 150 lights is professional grade, built with 20 gauge wire and suitable for both indoor and outdoor use. The strand has super bright lights on green wire. The set features straight-line construction, so even if one bulb burns out the rest will remain lit. The fuse-protected, end-to-end connector allows up to six sets to be connected together in a continuous strand of 900 lights! Use these lights in windows, trees, wreaths, topiaries and many more applications. Great for landscaping year round - winter, spring, summer, and fall. This set is UL listed for both indoor and outdoor use, and its high-quality construction allows it to stay lit even in the most adverse weather conditions.