seizes up pretty bad after some weight has been put on it while locked down. came with my metolious PAS. the seizing had happened on several occasions making for some potentially interesting situations. it now lives on my desk (i like to fiddle with things while reading). i won't ever have this anywhere on my rack again unless i'm also carrying a pair of slip-joint pliers, which i don't plan on doing. also takes roughly eleven spins to lock/unlock... frustrating piece of gear. do yourself a favor and get some positrons instead.