This set of 100 lights is standard grade, built with 22 gauge wire, and suitable for both indoor and outdoor use. The strand has super bright. 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. 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.