These feature a concave nylon tip that fits securely on the top of the Steersman Steering Guard grease fitting.
Mercury gear lube #92-802851A1 or
#92-802851K1
8 oz. tube (pictured below)
This method is much less messy than using a standard hand-operated grease gun. You will need to cut off a bit of the nozzle on the plastic tube to screw into the gun. The threads match perfectly. And as with grease, do not overlubricate. A little dab will do ya.