The Swigzy car cup holder adapter is designed for 2.8"-3.85" diameter bottles and cups. It is the original cup holder adapter with an adjustable base and rubber tabs to keep your bottle secure. The tabs are made from a proprietary material selected to make it easy to insert and remove bottles from the adapter. This ensures the adapter will not come out of your car?s cup holder when you remove the bottle to take a drink.The adjustable base is designed to fit most car cup holders (see picture with dimensions to ensure it will work with your vehicle) and adjusts from 2.6?-3.8? in diameter. Our extra thick pads on the expanding base ensure the adapter stays securely in your cup holder.The Swigzy adapter allows you to offset the bottom of the adapter with a single adjustment bolt. The benefits of the offset base are:Adapter will not block the adjacent cup holderTwo adapters can be used side by sideAdapter can still work where a center console lid, emergency brake, dash, or lid covering the car?s cup holders may normally prevent the adapter from fitting properly.The Swigzy adapter has multi-length tabs which allows it to hold most 20oz - 40oz bottles securely. Most popular brands of water-bottles will fit, including, but not limited to: Hydro-Flask: 32 oz. and 40 oz. Nalgene: 30 oz., 32 oz., 38 oz., and 48 oz. Yeti Rambler: 20 oz., 26 oz., 30 oz., and 36 ounce (14oz. will NOT fit) Klean Kanteen: 40 oz. Camelbak: 32 oz. and 40 oz. Takeya: 32 oz and 40 oz.Healthy Human: 32 oz and 40 oz.Gatorade: 32ozImportant! Please Read:To ensure the best results, an image with detailed dimensions has been provided. We offer a 100% guarantee and hassle-free refunds!*Patents Pending