This is a set of 1 X long wheel bolt with 2 X washers and 1 X lock nut that act as a shaft for the rolling as well as the stair climbing wheels.

*Repair Tip: This is a very important area of maintenance on your ZÜCA. These bolts are equipped with lock nuts and locking washers as well as lock-tight on the threads. Despite these measures it is possible that continuous vibration of travelling over rough surfaces can cause these bolts to work loose. If left unattended the loose bolts may damage the aluminum frame. Please watch the wheel tightening/setting video for details on maintaining these bolts.