This fixed rear sight is intended for a barrel up to 15/16" octagon. Tall, to reduce heat mirage, a square center notch is cut .070" wide by 0.10" deep. Wax cast steel, made in the Italy., the dovetail is about .350" long and .625" wide by .055" deep. Height from the bottom of the dovetail to the top of the sight notch is 0.45".