RWO's 11/16 in. (18mm) Medium Black Bullseye with a stainless steel liner is one of a full line of bullseyes. It is molded from high load-bearing Acetal resin to provide maximum wear resistance. The stainless steel ferrule liner works ideally with high-tech line. Its aperture is 11/16 in. (18mm). It measures 2 1/4 in. x 1 1/8 in. x 3/4 in. (57mm x 28m x 19mm).