Friction short ear. 360rotation of nock after attached to shaft. Less weight & bow string friction. Less than 3/16'' distance from shaft to bow string, allows decreased nock-to-shaft run-out. Fits Super Uni-Bushing shafts. Big mouth, flared openings. Works w/Ultra-Nok, Ultra-Nok II Micro, rope nocking loops, Gator jaw release aids & finger shooters.