How to use a grease gun. This is a typical grease gun setup. It has a replaceable cartridge which slides into the barrel of the grease gun. There's a foil that gets removed from this end of the grease gun and it simply threads into the actual trigger part of the grease gun like so and then the plunger is released and slid into the body. Now the end of the grease gun, it could be on a hose, it could be solid but the coupling is always going to look like this and it's designed to fit onto a zerk fitting, this is a zerk fitting, it has a check valve, it's a little ball bearing inside with a spring to keep the grease from coming back out and when you push the grease gun onto it, it just kind of sits there. Once the connector is connected, you simply squeeze the handle and the grease gets greased into whatever you are greasing and you can actually see the grease is starting to come out so you know it's getting into that particular caster bearing. And then to remove, you simply turn the connector slightly to the side and it pops right off.