Low silhouette, all steel front sight with eight interchangeable sight inserts that are locked into place by threaded cap. Sight includes insert set. Mfg: Lyman SPECS: Sight tube- 9/16" (14.3mm) dia.. Dovetail base is 3/8" (9.5mm) wide for standard dovetail. Use 17AML with 57SML Receiver sight. 17 ATC is for use with factory vernier tang sight on T/C muzzleloaders. 17AEU fits European 9mm (nominal .360" x .070") dovetail. HEIGHT is fr