This large, oversized solid aluminum Hammerhead knob is ergonomically designed to provide a secure grip on the bolt handle in any and all conditions. Features a contoured "waist" for pushing bolt knob up with your trigger finger. The knob installs easily on 5/16-24 TPI bolt handles like those on the Ruger Precision® Rifle. Machined from 6061-T6 aluminum and anodized red. 1" x 1" x 2" knob weighs only 1.5 oz. Made in the USA by Catalyst Arms.