The JPGS-5B model is our minimized small bore design intended to mount underneath many hand guard models on the market. This model also now includes our locking adjustment feature, which consists of an integral brass set screw that can be tensioned against the adjustment screw after it has been set to prevent any migration that might occur. Full coverage around gas port providing improved seal and better heat dissipation True clamp-on design with four positive clamping screws Easy to access side gas adjustment Specifications: Barrel Diameter: .750 Material: 416 stainless Finish: Black Weight: 2.25 oz. Length: 1.28" Height: 1.40" (overall), .78" (over bore) Width: .89" Attachment: 6-32 x 1/2" socket head screws, T15 Torx drive (included) (includes 5/64 x 5/16 roll pin for gas tube installation) Adjustment: 6-32 x 3/8" set screw, 1/16 hex drive (included)