I was changing the oil in the rear end of my truck,when it came time to fill it back up I was going to use a suction gun,but I find them messy. Looking at the neck of the bottle it looked as though it might be the same size as the extension part of this cheap 2-piece funnel . Sure enogh the bottle screwed right on!I just lifted the whole works up like an I. V. bag and took a knife and poked thebottle to let air in. With the price of Amsoil you dont want to spill a drop. Most of you guys probably do something similar but maybe it might help someone