This Fits Acura Legend. 5-Groove Pulley. Regulator OEM No. 126000-1170 ("S-FR-IG-L" ). This is a Large Case (137mm) Unit w/17mm Rotor Shaft. The 13685, Used on Later Acura's, Looks Just Like the 13387 (Also 110A - Also Using a 5-Groove Pulley), But Has a Ground Tab on the Rear Cover. The Regulator Used on the 13685 is #126000-1280.