Applicable to 18.9 litres of water bucket, Inner caps design turn the non-spill caps into reusable and replacement; say no to lots of disposable water caps | Not for use with screw top bottle, Please check product images to see the bottle these will fit,corrosion preventive. | No splash, not easily deform,clean and durable.Save money by using WINBOB non-spill bottle caps. | White inner inset, air-tight foam, dust-cover could be taken off as you need. | Sealing strong, seal ensures sterile environment & protection against spillage.Refill your water jug for recycling use and saving your money.