Do you own an early model RWD Nissan car and want to change your own transmission fluids?  After only one attempt at changing your fluid, will you realize that the square transmission fill plug requires a special socket to remove.  Otherwise you are most likely going to strip it.  This socket will make your routine early Nissan RWD transmission fluid changes a breeze; especially if your fill plug has not yet been removed and still have the original torque setting from the factory along with thread lock on there.  Up until our introduction of these sockets, the only tool people thought to use on the fill plug was a sloppy adjustable wrench.  This 17mm square socket is a perfect fit over the square male fill plug.  Just fasten this on a 1/2" drive ratchet to use.  Unecessary effort is wasted holding a slipping adjustable wrench over that fill plug.  Wondering if there is a real tool for this job?  This is it.  Use this socket with any standard 1/2" drive ratchet or 1/2" drive breaker bar, but not for use with impact equipment.  This socket is especially helpful to those who have upgraded differentials and transmissions, even enthusiasts who often participate in track events where frequent fluid changes are necessary.  For the drain plug you will need our KTC 13mm socket found here.