What is Lock-Pin? Lock-Pin is the only interlocking tool designed to retighten hair locs and dreadlocks without slipping off. Ordinary interlocking tools can easily slip off locs, and additionally it can be difficult and painful to pass the tool and loc through the base of the loc. Lock-Pin is designed to make it faster and more comfortable to tighten and retighten dreadlocks without slipping. Lock-Pin features a unique slim, curved design with a sharp needle that can be used to hook and securely attach the loc. Lock-Pin is easy to use—simply open the pin to capture the dreadlock, close the pin to begin interlocking and tightening the loc, then open the pin to release.