The arm rest must be ordered when replacing the wrist strap on either SureGuard® Safety Restraint Chair, or its Junior model. Because of the design of the included strap, you must purchase a specific left or right Arm Rest with Strap. This is the Left and the regular length of the wrist strap is 28". Does not include a cam and spring set. These must be ordered separately and roll pins are no longer needed or used.