This is a Berg Larsen metal “Straight Bill” 110/1 M metal mouthpiece for tenor saxophone. The piece shows some standard play wear across the body and bite plate, Its black bite plate is not the prettiest but there is no major indentations from past use. At some point in the past someone did some facing work on this piece. You can still see the side to side mill markings on the table.
This piece plays with a pretty focused response and a medium bright sonic character. Its current tip opening measures .102”.