RWO's 1/4 in. (6mm) Small 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 3/16 in. (5mm). It measures 1 3/16 in. x 1/2 in. x 5/16 in. (30mm x 13mm x 8mm).