Patent-pending design. Compatible with 32 and 40 ounce wide-mouth Hydro Flasks and similar bottles like Iron Flasks, Takeyas, and ThermoFlasks. The thin-wall design fits around the insulating center of a Hydro Flask cap. Does NOT work with wide mouth Nalgene bottles.
Low flow and high flow sides can be used, depending on your preference.
Keeps ice from flowing out of your bottle or splashing water in your face.