This Lyman manufactured No. 42 receiver peep sight is for the model 19 NRA, 23 series rimfire and centerfire Sporters, and the model 3, 4, & 5 bolt action rimfire rifles and is unmarked except for the manufacturers name on the base portion. This sight has the fold down (forward) peep and is threaded for an eye cup (not present). The overall condition is very good exhibiting a brown patina mixed with original blue finish. The two mounting screws are included. Your rifle may require drilling and tapping to install.