This beautiful boss is modeled after one found in Telemark, Norway and dated to the 10th century. Hand hammered from 1.5mm iron and comes with 4 iron rivets. 4 holes in rim are just under 1/8". Boss weighs about 3/4 of a pound. Outside rim is about 6.25" diameter, inside dome is about 5" diameter. Rim is about .5", dome is about 3" tall.