You can easily fasten both commercial-grade and standard-grade lights to buildings and trees with these tie wraps. They can be used with C7 Lamps, C9 Lamps, and Mini Lights. The ties work for both standard Incandescent and LED's. Each tie is 6" and the black color is designed for use with black wire and for night displays. Come in bags of 500. They are good for both indoor and outdoor use.