Introduced in 2017 is an industry 1st in probably 20 years. Sling packs especially need super-reliable buckle lock-up since the pack drops if they disengage. Every pack brand has used no locks or a stock lock-buckle. Ours is a better design that locks totally, can't disengage inadvertently, has big parts that are unlikely to fail/tolerate moulding flaws better, and is easy to repair. It also allows the male part to unlock the switch if in the locked-position. Anyone familar with an AR15's safety will know exactly how it works. But this can be used with thick gloves. It is being rolled out selectively to 2" webbing positions - like in our Plan B '17 modernized sling pack (slings page). Use this as a spare or replacement buckle for Hazard 4(R) products.