Make your Hydro Flask your own with a colorful, durable silicone Bottle Boot that protects against bumps and dings. Specifically sized to fit our 32 oz and 40 oz Wide Mouth bottles. DETAILS Fits 32 oz and 40 oz Wide Mouth bottles Medium boot is not compatible with 32 oz or 40 oz Lightweight Wide Mouth Trail Series bottles Removable, silicone boot adds extra protection to your Hydro Flask bottle. BPA-Free Dishwasher safe Not for use on a stove, in a microwave or freezer.