Rosco Barrel Swivels are used to prevent fishing line from becoming twisted, which can cause stressed, frayed, weakened or tangled line. Swivels can also be used to link 2 pieces of line together, or to attach a line to a leader. Very durable, Rosco Swivels will pivot freely and are made with anticorrosive material to avoid freezing up. Per 36. Length: 3/8. Lb. test: 20. Color: Black. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Barrel & Crane.