Carlson’s Hammer Expander provides easy cocking for left- or right-hand use at all times. Balanced and lightweight it is easy to install and helps prevent uneven wear of trigger and sear surfaces. The knurled body affords positive non-slip cocking and it may be used with or without telescopic sights. The hammer expander is .375″ in diameter and 1.5″ in length. Made in USA. This model has a black hard anodized finish and is compatible with Henry Big Boy rifles (post 2010).