Abstract: A security device for weapons that makes them inoperable with a mechanism that can be readily installed. A plate assembly has a locking assembly mounted thereon with a retractable tongue. A spaced apart rigid assembly mounted on the plate assembly receives the distal end of the tongue. A weapon's trigger is lodged between the plate and the tongue and between the locking assembly and the rigid assembly. A user activates the locking assembly with a key to selectively make the weapon's trigger inoperable and inaccessible.