To me, its sad that a product like this has to exist in the first place, but exist it does. The UBML, an apt shortening of “Ultimate Bilateral Magazine Lock” is a ambidextrous pair to the “bullet buttons” required by states or countries that various restrictions on self-loading rifles.
Thordsen Customs (who also makes a great pistol buffer tube) is now on Generation II, which features the usual technical specifications for rugged products. The UBML is machined from 6061 anodizing and mates to a slightly customized standard magazine release. Finished in Type III hard black anodizing, its battle-ready (or as battle-ready as a magazine release that requires a tool could be).
Basically, it adds the same “bullet button” functionality to the left hand side of the rifle, of which “Competition shooters and tactical training junkies can benefit greatly.” (Another personal shudder…). But, it certainly has practical implications for letting the off-hand easily swap out a magazine.
The kit is compatible with forged and a few billet receivers, but Thordsen Customs does not explicitly claim compatibility with any specific model. The UBML is compatible with most aftermarket bolt catch devices including BAD Levers and their associated derivations.
Retail for the kit is set at $54.99 (which is at least better than a Norgon for us in non-restricted states). Armorer knowledge and tools are required for installation.