I know they don't have the "name," but I have been using UTG Slim M-LOK. It IS very firm and stable. No flex either on bags. solid barricade, or hand held.
It comes with their barrel nut, attachment collar AND the wrench--unlike ALG. It uses two screws each at 3, 6, and 9 o'clock. To me that's much more solid than something that only clamps at the bottom.
It was an absolutely perfect fit with the Spike's upper without putting a picatinny device in to cinch them together. It comes with a 3-slot picatinny section, a QD connector you can mount where you want, and 1.25" QD sling device.
Don't confuse this with their M4/AR15 PRO series. A little cheaper because they don't have to do keymod or M-LOK cuts. Rounded except for the top rail section. It DOES need their proprietary stuff around the sides, but they give you three picatinny sections initially.
BTW- If you are military, veteran or LE, they give you 25% off for a direct order over $50--and free shipping.