Precision Armament TBK-10 Tactical Bolt Knob Aluminum 1/4-28 Thread Matte Black. Sure-Grip provides a dependable non-slip surface for fast reliable cycling without being sharp or abrasive like knurling. Available in 1/4-28 and 5/16-24 threads and is slightly reduced in overall size (compared to standard oversize knobs) to better fit smaller diameter bolt handles such as the Winchester M-70 and Savage 10/110 rifles. Mil-A-8625 hardcoat anodized matte black finish. Specifications for Precision Armament TBK-10 Mini Tactical Bolt Knob: Manufacturer: Precision Armament Fabric/Material: 7075-T6 Aluminum Finish: Mil-A-8625 Hardcoat Anodized Country of Origin: USA Package Contents: Precision Armament TBK-10 Mini Tactical Bolt Knob Precision Armament A05004: TBK-10 Tactical Bolt Knob Aluminum 1/4-28 Thread Matte Black