Genuine Lucas Classic HP26 Horn Push Assembly 76200, for use on: BSA models Bantam (1950 - 1953), C10,C11 (1939-55), C12 (1956-57). Triumph models: 3T, 5T, TR5, 6T, TR6, T100, T110 (1946-58). Norton Twins (1953-55), Ariel 350, 500, 650, 1000(1954-57). AJS/Matchless models (1950-57)Royal Enfield 250,350,500 models (1955-56). AJS/Matchless models (1950-57). Royal Enfield 250, 350, 500 (1955-56).
Type: Screw into Handlebar 
Screw Thread: 3/8" CEI 26TPI
O.E.M: 76200 / HP26 / 76200A