PERFECT FIT: Designed to fit Hydro Flask 32 oz (946 ml) and 40 oz (1,182 ml) Wide Mouth bottles for a secure fit. DURABLE SILICONE MATERIAL: High-quality silicone construction provides long-lasting protection and a reliable grip. ENHANCED FUNCTIONALITY: Improves stability and prevents sliding on surfaces for everyday convenience. EASY TO CLEAN: Dishwasher safe and simple to remove for hassle-free maintenance. EXTRA PROTECTION FOR YOUR BOTTLE: Hydro Flask Medium Bottle Boot shields your bottle from bumps and dings for added durability.