For all those looking for the lightest, smallest ARCALOCK rail on the market - here ya go. Weighing in at just 1.5oz, this will fir forend hole spacings of 2a ^2-3.5a ^2, just like our extremely popular IBR. The rail will also come with t-nuts and hardware to allow you to install the rail closer to the magwell for tripod use. MLOK HARDWARE NOT INCLUDED These rails are made of 6061 billet aluminum and will be sold only in a black hardcoat anodized finish.