Made in the USA for Henry by Evolution Gun Works. 

The rear sight must be removed on all models in order to provide clearance for the base. This is a simple operation as the sight is pressed into a standard 3/8" dovetail.

Be sure the firearm is unloaded, then use a blunt punch(brass, wooden dowel, etc) to drive the sight out from left to right as the muzzle is pointed downrange in a safe direction.