The Lyman 20 Series Globe Front Sight features a larger 7/8" diameter tube and offers the shooter a brighter and larger field of view. Includes two post and five aperture inserts. Accepts Anschutz style inserts. Blued steel. 3/8" dovetail. Height is from bottom of dovetail to center of aperture. Kit Includes:Two post-type inserts (.067 and .102 wide)Six steel aperture inserts (.126, .133, .154, .161, .169, .177 hole size)