Black plastic screw caps are tight, sealed to prevent leakage. The glass for bottle is  thick and premium, makes the bottle strong and durable. The brown glass boston bottles are suit for kombucha, liquid,  essential oils, perfume, or homemade extracts. Volume: 15ml, 30ml, 60ml, 120ml Refillable glass empty bottles,  can be reused for much time possible. It’s durable and reusable …