The M-LOK QD swivel sling adapter is not unlike other MLOK sling adapters in the market, except MSQ-H (M-LOK, Sling adapter, QD, Heavy) is billet machined in 4140, and black nitrided. MSQ-H is the first of several collaborations between Forward Controls Design and Sons of Liberty Gunworks. It is based on an existing product from Arson Machine. Heavier than the aluminum sling adapters, it is also stronger (4140 tensile strength is 95,000psi, vs 7075 T6 tensile strength of 73,000psi, and 6061 yield strength of 40,000), we gladly accept the tradeoff for better durability. MSQ-H weighs in at 0.867oz. It's not meant to be light; it is meant to be durable. M Mfg: Forward Controls Design