T-Screw Security Wrench | T Screw Wrench | T Lock Wrench for Security Picture Hangers - Set of 2 2 Sizes of Security Wrenches to turn T-Head Security Screws Used with picture security hardware to install (lock) or uninstall (unlock) art from the wall Short Wrench can reach 2 inches behind art/frame Long Wrench can reach 6 inches behind art/frame Hardened Wrench has a stronger notch that will securely fit on the t-screw without slipping