REVIEW: The Folding Full-Conceal Glock. “The patented M3D is, in essence, a Gen4 Glock 19 with a hinge in the front strap and a spring-loaded latch in the back strap. Press the latch and the entire grip folds forward to lie against the dust cover, parallel to the bore axis. Perhaps uncoincidentally, the folded package is more than a little reminiscent of the G26-plus-spare-magazine package that Full carried before the Kahr. In order to accomplish this feat of origami, the trigger guard is replaced with a hinged assembly that collapses flat between the grip and dust cover.”