Description Searching of bottle caps? Our bottle caps will be the best choice for you. Made of high grade ABS material, durable enough for your long-term use. Practical and portable design, ensures its popularity. Features - Color: Grey. - Material: ABS engineering plastic. - Size: About 3.00X3.30X3.30cm/1.18X1.30X1.30inch. -Made of high-grade materials, safe and durable, you can use it with confidence. -These bottle caps are suitable for most kinds of carbon dioxide DIY reactor. -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 setup, the bottle caps are helper when they are doing the process of generating . -Easy to set up, and high grade materials, can be used for a long time. Made of high-grade materials, safe and durable, you can use it with confidence. These bottle caps are suitable for most kinds of carbon dioxide DIY reactor. 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 setup, the bottle caps are helper when they are doing the process of generating . Easy to set up, and high grade materials, can be used for a long time.