a housing having front and rear ends and defining an interior area at said front end for selectively containing a portion of the bow string;

a barrier for selectively separating said interior area from an area external to said housing, said barrier being movable from an open configuration in which the bow string may pass between said interior area and said external area and a closed configuration in which the bow string may not pass between said interior area and said external area;

an extension coupled to said barrier, said extension being inside said housing and extending toward said rear end of said housing;

a trigger coupled to said extension and being selectively movable for selectively moving said barrier between said open and closed configurations;

a trigger guard extending from said housing and around said trigger to protect said trigger from accidental movement;

a trigger lock selectively restricting movement of said trigger, said barrier, and said extension by abutting at least one item selected from the group consisting of said trigger and said extension, wherein said barrier is immovable from said closed configuration when said trigger lock is activated; and

a spring that interacts with said extension to bias said barrier to said closed configuration.