The Owala silicone water bottle boot is designed to fit 40-ounce FreeSip or Twist stainless steel water bottles. It is not intended for use with the tritan plastic water bottles, nor 25- or 19-ounce bottles. The silicone boot is like a phone case for your water bottle - it protects it from scratches, dents, or zombie attacks. It absorbs any damage that comes its way. Offered in bright colors to mix and match with your favorite Owala bottles. Owala water bottle not included. Dishwasher safe.