Riser kits increase stack height to fit a wide range of riding styles for efficient positioning; compatible with ZBS Aerobars, T Plus Carbon Series Aerobars, T Plus Aluminum Series Aerobars, Supersonic Aerobars, Sonic Aerobars, and Subsonic Aerobars. - Multiple kits can be used to reach desired height up to 80mm rise - Raises armrest and extensions together to maintain a comfortable wrist position - Kit includes a pair of risers, bolts specific to riser size, and mounting hardware - Risers are compatible with J2, J3, and J4 Aerobar brackets - Clamp diameter: 31.8mm