Precision-machined, buckhorn, rear sight and base include screws that fit the holes in your Wesson & Harrington rifle for drop-on, no gunsmithing installation. Slider has a detent that lets you feel each adjustment; setscrew locks into place. Ladder has side markings so you can easily repeat the right yardage settings. Drift adjustable for windage; setscrew locks your setting. Mfg: Smith Enterprise SPECS: Machined steel, blued finish. Sight - Ladder has approximately 1-27⁄64" (3.6cm) height adjustment; Buckhorn aperture 5⁄16" (8mm) I.D. Base - 19⁄64" (7.5mm) high from bottom of receiver to top of base, 2¾" (7cm) long, 5⁄8" (15.9mm) wide.