Leviton C0265-I telephone security lock / phone security lock. Compatible with both 4 and 6-wire modular plugs. Plug in back plugs into common phone wall outlet modular phone jack. On right side are two modular phone jacks. Top phone jack is for outgoing calls, bottom phone jack is for incoming calls. When locked, incoming phone calls are unimpeded. However, except for "911" calls, all outgoing calls are blocked - only 911 calls allowed to go through. Keys included.
