Using waterproof double-sided tape with robust adhesion, these clips are apt for both indoor and outdoor use, through summer and winter, and can withstand wind, rain, high temperature, storms, snow, hail and other harsh weather conditions. They excellent fixation and protection for your string lights. Be aware that the hook might not adhere well if applied on or uneven surfaces. For optimal stability, it is recommended to use the hooks on smooth surfaces and these surfaces are clean prior to installation. The packaging of each clear outdoor light clips set includes 30 clear hooks and 30 Waterproof adhesive backing. The dimensions for each clip are 0.6inch L x 0.55inch W. Our outdoor string light hooks come with highly adhesive stickers that are straightforward to install, requiring no tools and can be done by one person. They provide robust strength and can be easily taken off without leaving any undesirable residue on walls. These hooks stick to any dry and smooth surfaces like wood, metal, glass, French , ceilings, solid walls, and tables. They are suitable for doors, tiles, , flat walls, soft cornices, finished fences, metal, and wood surfaces. They are not recommended for use on rough, wet, oily surfaces, as well as wallpaper and walls.