The plastic gasket is way nicer than only having a lid liner. These work great for storing concentrates, uh, I mean jam, yup jam that's it. FYI if rosin is your poison note that if you use the gasket, that will cut into capacity ever so slightly enough so that having some 9ml jars on hand as well is never a bad idea. If you're using distillate, then terping it will be not very much fun if you need to get the disty off the gasket first. You can probably fit more without any issue, depending upon density/consistency, but I generally don't put more than 2g in one of these--never any stickage after adopting that rule.Onto other potentially relevant areas--there's no child-proofing to make your life any harder, and I've never once had one of these leak. And the place I order from uses the exact same jars, and I've had stuff oriented every which way, even upside down, and still no leaks (knock on wood). At the going bulk rate you really can't go wrong.