This magazine features a patented Double Helix rotary box magazine which uses torsion spring-driven interlocking gears for added reliability. It is constructed of metal floor plate with a polymer body. The translucent gray body allows for easy verification of the number of remaining cartridges. Cartridges shown not included. Type Detachable Model T-Bolt Finish Black Caliber 17 HMR Capacity 10 Material Polymer Brand Fit Browning Model Fit T-Bolt