1. Insulation Material The bike cup holder is made of Oxford cloth and insulated thick aluminum foil material, which is waterproof and heat insulating. It can keep your drinks cool in hot weather and warm in cold weather. 2. Self Adhesive Tape Pull Cord Design The self adhesive tape and pull cord closure of the bike cup holder secure your bottle easily. It ensures a firm grip even on bumpy rides and protects water bottles and mobile phones from falling. 3. KEEPS YOUR BOTTLE TIGHT With a two point attachment design, the bike cup holder stays in place and attaches securely to your bike, even on rough mountain trails. It fits roll cages with a diameter of 0.4 to 3 inches without compromising driving stability. The water bag also has a drainage hole at the bottom for easy cleaning and drainage. 4. FITS MOST WATER BOTTLES The bike water bottle holder features a drawstring design that retracts , making this multifunctional accessory whether you're riding a bike, scooter, or pushing a stroller for a walk. Carry your water bottle or cup with you wherever you go.