Hydro Flask 18oz Standard Mouth Flex Cap Rain. Strong yet flexible our Standard Mouth Flex Cap is the perfect companion for spontaneous campouts epic road trips and everything in between. Made with stainless steel pivots and an easy-to-carry strap this cap has Honeycomb Insulation to help keep your drinks cold for up to 24 hours or hot up to 12. Pair it with any of our Standard Mouth bottles. Specifications for Hydro Flask 18oz Standard Mouth Flex Cap: Manufacturer: Hydro Flask Color: Rain Size: Standard Gender: Unisex Application: Outdoor Quantity: 1 Volume: 18 oz Capacity: 18 oz Features of Hydro Flask Standard Mouth Flex Cap: Leak-proof design Vented cap allows hot vapors to escape Made of durable polypropylene PP#5 BPA-free Compatible with all standard mouth bottles Lifetime Warranty Package Contents: Hydro Flask 18oz Standard Mouth Flex Cap Hydro Flask S18SX417: 18oz Standard Mouth Flex Cap Rain Hydro Flask S18SX417: 18oz Standard Mouth Flex Cap Rain