Cup Keeper is a patented plastic adapter allows a mug, cup, or bottle to fit in your vehicle’s standard cup holder. Fits most cup holders. Holds mugs, convenience store cups, and bottles. Durable, dishwasher safe, and portable -- move from car to golf cart to truck to boat to RV! Cup Keeper simply sits in existing cup holders and expands the opening. Color: Black. Dimensions: 3.5" diameter top of cup, 2.5" diameter bottom of cup.