This Ruger manufactured .400" +/- high front sight with integral ramp is for the Mark I semi-auto target pistol which is equipped with the adjustable rear sight and a bull barrel. This sight is in very good condition with light wear and possibly a few specks of rust. (file photo)

Overall Measurement: .440" +/- High

Note: Ruger Mark I semi-auto target pistols with the following serial numbers have been observed with this part:

5 1/2" Barrel: 10-90939