The rubber grip is an additional protection for GUB bicycle grips. It protects the device on the bike mount, preventing vibration while riding. Fits most devices. Universal: the rubber grip fits most central grips, such as GUB or RAM. Flexible - stretch to fit most devices. Stiffens the phone, so it prevents the device from falling out while driving and improves the comfort of using the phone. Thoughtful design does not block access to the function buttons and ports.