One Buyer's Comment:Good seal.I like the liners on these lids. The lids have a very thin liner made out of a plastic that feels slightly waxy & has a little bit of give. While thin, it still is substantial enough to allow me to pry up with the edge of my nail & remove without damaging it, if I want for washing. It seems more likely to last than most foam liners I am familiar with. The lids still screw down tightly, easily, even without the liner. I took the liner out of one, and tested the tight The capacity is 1oz (30ml),made of durable aluminum, which have the features of luster, waterproof, corrosion-resistant, eco-friendly, light weight and convenient to carry. Perfect for DIY lip balms, pills, party favors, candies, mints, vitamins, skincare, makeup samples or loose leaf teas, herbs, medication etc.