Pay Attention: Adjustable base fits size of round car cup holder (2.4"-3.6"), upper cup holder expander fits size of bottles, mugs, cups (3.4"- 4.0"). Before placing an orde, please confirm whether your car cup holder shape meets our product, and our product is free returns and exchanges within 30 days. ✓?U-shaped Slot Design: Unlike other traditional cup holders, u-shaped slot is very convenient for cups or mugs with handle can perfectly be placed in this car cup holders without tilting or splashing. ✓?Fits Most Cups: CiWiVOKi cup expander for car can holds Hydro Flask, Yeti, Nalgene, Contigo mugs, Bottles & Big Drinks. Suitable for most cups (size:3.4"- 4.0"). ✓?Rubber shrapnel & car cup coaster: There are 4 rubber shrapnels on the inner wall and a coaster at the bottom, which make the cups/bottles/mugs more stable during driving. ✓?Car Cup Holder Expender: The expandable base can adjust to fit different kinds of automotive cup holders from 2.4"-3.6" in diameter. Just twist the base of the adapter to expand or retract the base and it can be firmly fixed on the car cup holder.