The Mustang Passenger Backrest rear seats extends forward to provide ample back support for the driver, and comes standard with the straight driver backrest post as shown in the picture. The Mustang offset backrest post ZZ86543 , can be used for those passengers who want to lean farther back. The backrest post can be adjusted for different height settings, and can be locked into place using the supplied knurled thumbscrew at the back of the seat The tilt angle of the backrest pad can be adjusted forward and back using the thumbscrew on the back side of the upper post The backrest upper can be folded flat for ease of mounting and dismounting The passenger backrest should be folded flat when the cycle is ridden without a passenger