Here, side by side you can see the drastic difference between an OBDI Injector (pictured LEFT) and OBDII Injector (pictured RIGHT) NOTICE THE SEALS.. The top of the injector you can see the same 11mm o-ring used, body construction is very similar until you reach the half way point of the injector The OBDI Injector DOES NOT HAVE A SECCONDARY LOWER SEAL OBDI Injectors only have the upper 11mm o-ring, the Toytoa/Honda style step seal and the Toyota/Mitsubishi style lower seal