The NutFix system protects seatposts against theft thanks to a physical trick and it can be opened with a standard wrench if necessary FEATURES : Replacement lockable seatpost clamp Anodized surfaces of the caps provide long-lasting protection against corrosion Secure closure by innovative gravity technology Caps can only stand out to release the wrench flats when the bicycle is on its side Nuts are made of stainless steel Uses standard 8mm spanner wrench to secure clamp