AEM cam angle sensor discs are for use with AEM programmable engine management systems They are a direct replacement for the factory crank angle sensor disc in your Nissan. Before purchasing the 24 Nissan CAS sensor, be sure that the center of the AEM CAS disc looks exactly like the stock disc in your distributor. Be sure to match the hubs of your disc to the AEM Nissan CAS sensor disc before ordering. Fits Nissan RB25DET and some RB26 - 50mm OD