Tank Ring And Adapter Plate: Quickly and securely attach PRO tank bags to the tail. PRO tank ring is attached to the adapter plate using four screws and makes it possible to snap on PRO tank bags with level bottoms. Made from rugged, glass fiber reinforced synthetic material. Included in delivery: One PRO Tank ring for STREET-RACK: Secures PRO tank bags on the adapter plate for STREET- RACK. Quick-lock function makes it easy to snap on tank bag models such as PRO Micro, PRO Daypack, PRO Sport, or PRO Engage (all sold separately). Easy assembly; PRO tank ring is screwed onto the adapter plate. Fiberglass reinforced plastic construction. One Adapter plate for STREET-RACK: The adapter plate can be securely locked to the STREET-RACK without the use of tools.