12.5 = 1/2 "¢ square connection, DIN 3120, for socket applications.
mm / SW inches: 17.0 x 19.0 x 22.0 mm x 12.5 = 1/2 "Length: 380.0 mm TYPE: CROSS SPANNER PROFILE: HEXAGONAL SIZE / SIZE: 17 MM LENGTH: 380.0MM SHAPE: STRAIGHT WITH CARDAN: NO WITH RATCHET: NO GAME: YES