The set of Stilettoz comprises three steel spikes for 3 Legged Thing tripods. They help stabilize your tripod on various surfaces such as rocks and other hard or soft terrains. The Stilettoz are slightly longer than the company's Heelz spikes, for terrain that necessitates longer spikes for embedding in softer ground to provide a firmer anchor during windy and turbulent weather. Each Stiletto has a standard 1/4"-20 thread and a 3/8"-16 bushing for users who wish to use the accessories with other brands of tripods that use either size. Stilettos are compatible with all 3 Legged Thing tripods.