Ideal for use in cars, trucks, SUVs, recreational vehicles such as boats, RVs, and more Compatible with 32/40 Ounce Hydro Flasks, Iron Flasks, Takeyas, Simple Modern, Nalgene, Klean Kanteen, Thermoflasks, Fifty Fifty Adjustable base that securely fits the majority of cup holders. This simple but effective design works with most standard cup holders that are circular with an even rim around the top. Expandable base adjusts to fit into most vehicle cup holders between 2.5-3.75 inches Flexible rubber grip tabs inside allow you to place and remove cups and bottles Our HDXCUP Drinks Beverage Expander Cup Holder Adapter Mount is made with Simplicity in mind, It is easy to setup and adjust and compatible with all 20/26/30/32/40 Once Tumbler Mug from Hydro Flasks, Iron Flasks, Takeyas, Simple Modern, Nalgene, Klean Kanteen, Thermoflasks, Fifty Fifty & many others


why you need a car cup holder?
The original cupholders were deep enough to hold most drinks but didn't have any top support. So they would tilt around and rattle a bunch or fly out during a turn. With this cupholders there's no rattling and the drink is held in place very securely.