CUP HOLDER EXPANDER FOR OVERSIZE BOTTLES/MUGS: The 4, rubber tabs keep most oversize (3.4”-3.8”) bottles or mugs securely in place. Perfect for certain versions of Hydro Flask, YETI, RTIC, Nalgene, CamelBak, Klean Kanteen and more (does not fit 14oz or 46oz YETI Ramblers). Please compare bottle dimensions to provided product dimensions before purchasing. 3-RING EXPANDABLE BASE: Adjustable base has an expandable diameter from 2.5"-3.75". This allows the adapter to stay firmly in place, regardless of how rough the terrain gets. Please compare your vehicle cup holder to this product before purchasing. This model works best in cylindrical cup holders. It does not work well in most square cup holders or cup holders that are recessed into the console. SLOT FOR COFFEE MUGS: The 1 inch slot is integrated into the design so coffee mugs will fit with ease. This is perfect for the popular YETI 24oz Rambler (14oz Rambler does NOT fit). Please compare dimensions of desired coffee mug to the product dimensions before purchasing. EASY INSTALLATION: Just hold the base and twist the top, the base will then retract or expand. Comes with instruction card. UNIVERSAL: Fits in almost anything with a cup holder; such as vehicles, boats, RV’s, UTV’s, etc. However, some cup holder designs will not work. PLEASE REVIEW THE PICTURED DIMENSIONS TO ENSURE A PROPER FITMENT BEFORE PURCHASING. The Integral vehicle cup holder expander is specifically designed for a broad range of fitment. This adapter fits perfectly in most vehicles, RV’s, boats, golf carts, motorcycles, etc. However, due to the large variety of vehicle cup holders, in certain applications this adapter will not fit. We ask that you please view the dimension photo and compare it to your specific application. Cup holders that are located in vehicle doors, have anything directly above them, are located on a steep angle, or have covers may not work with this design. We offer 100%, full product refunds due to the large variety of fitment