The original wired nut that helped launch the clean climbing revolution has continually evolved to remain the standard by which others are judged. Black Diamond Stoppers aluminum alloy is durable yet has plenty of bite to sit in rock ranging from bulletproof granite to sandstone. Anodized by size for quick identication, Stoppers have a unique transverse taper that increases surface area contact to provide the best placements possible in non-parallel cracks. Sculpted and optimized for easy placement and removal, Stoppers have rounded corners that dont get hung up on crystals and irregularities. Time-proven design is light, strong and easy to use. Transverse taper allows good placements in funky cracks. Anodized for easy identification.