Versatile, steel bases accept target front sights and external adjustment scopes from Redfield, Lyman, Unertl and others that require a 3/8'''' dovetail base. Contoured bottom radius provides a tight, solid fit to barrel, prevents side movement, and ensures base is aligned squarely with receiver. Does not fit Redfield external adjustment scopes. Mfg: P&L Development SPECS: 1018 steel, blue, matte finish. 1-15/16'''' (3.5cm) long. 9/16'''' bottom radius. Hole spacings are .860'''' and .562''''. Includes 6-48 screws.