Tunnel Sight with twelve interchangeable insertsFeatures: Works perfectly in conjunction with Creedmoor rear sights Steel construction Matte blue finish Inserts are locked in place with knurled, threaded cap Interchangeable inserts allow you to select the best sight picture for the current distance and range of your target Mfg: Davide Pedersoli S.R.L SPECS: Steel, blued. Dovetail base - 3/8" x 30o - H .350".