Be careful with the 18g. I have had a few times in the last few weeks that when I push the 18g through the stopper, its so big and open that it takes a little chunk of stopper off. then I dont see it till I draw the oil in the barrel. Thats a fucking pain in the ass. MAYBE I have shitty rubber stoppers on my vials. But I think I may switch to 20g to draw with soon as I run out of 18g.