1.LEAK-PROOF & AIRTIGHT SEAL: The integrated silicone gasket provide a secure seal to leak-proof, easy to use, simply screw the lid on jar and then press flip cap hard for leak-proof. The airtight seal keeps your food fresh. 2.EASY POUR: The flip cap stays open and out of the way when you are pouring or drinking, it will never flop back down and get in the way of the stream. The flip cap is securely attached, it will never flipping back down without force. 3.SAFE& DURABLE: The ergonomically designed thicken handle is made of high-quality food-grade BPA material could support the weight of a full jar, without bending at all and easy to hold and use. 4.REBLE 4 PACK LIDS SET: Reusable canning lids use with WIDE & REGULAR MOUTH Ball & Kerr jars to replace plastic water bottles and disposable to-go containers. Use it on your mason jars or other bottles and jars, just put in a straw and they become drinking lids.