Searching of CO2 Bottle Caps? Our CO2 bottle caps will be the for you. Made of plastic material, enough for your long-term use. Practical and portable design, its popularity. Plastic material makes this bottle uneasy to rust and safe for your fish and water plant. And it can be your good helper. Features -Color:Beige -Material:Plastic -Size:4.00X3.80X3.80cm/1.57X1.49X1.49in - Easy to use. Just screw the bottle on the drink bottle. Easy and sealed without letting the air out easily. - For people who love DIY CO2 setup, the bottle caps are helper when they are doing the process of generating CO2. - Easy to set up, and plastic materials, can be used for a long time. - Made of plastic materials, safe and , you can use it with confidence. Standard , widely applicable. - These CO2 Bottle Caps are suitable for most kinds of co2 DIY generator. Package list: 2