One Arm & Two Arm throttle quadrants work with Rotax® engines but require an adapter kit for installation of both throttle & choke cables to the quadrant. Installs on most Ultralights. Includes friction control knob. The one arm quadrant weighs 1/2 lb. and is 4" wide and 7-1/2" tall. The two arm quadrant weighs 1 lb. and is 4" wide and 7-1/2" tall.