The Accessory Rail Small shares the same rail interface as the SMB and the LMB Accessory Adapter. Two ball-pressure pieces on each side of the rail prevent an attached Accessory Rail Bracket ARB-1 from slipping off. It is compatible with all 3/8"-16 interfaces which offer holes for the two securing pins. Four different-sized hex keys can be used with the Accessory Rail Small without having to adjust it - 3, 4, 5, and 5/32" sizes will all fit.