J.A. STEIN freewheel grease injector. This also works great for flushing out stuck freewheels. If you’re working on bikes that use a freewheel and commonly need to fix, repair, restore, or overhaul freewheels for any reason. This tool is great to have in your kit. Just screw on to any standard freewheel and off you go! This one comes with the injection port, but this can also screw off and you can use larger plastic syringes to flush out a freewheel with your choice of solvent. The rubber seal is also still in great condition.