Hydro Flask Standard Mouth Flex Straw Cap

New Hydro Flask Standard Mouth Flex Straw Cap in black. This accessory fits all standard mouth Hydro Flask bottles, including 18 oz, 21 oz, and 24 oz sizes. Each pack includes one leak-proof flex straw cap and two straws that can be trimmed to the desired length. The cap has a flexible strap for transport and honeycomb insulation for temperature retention.