* All components are designed to work with MBX tubes.
Other manufacture parts may be used in conjunction with MBX parts,
components, or tubes but may require adjustment/fitting for maximum reliability.
11" Spring: For use with STI / Para / Armscor Style 140mm & 126mm tubes.
13" Spring: For use with STI / Para / Armscor Style 170mm & 155mm tubes.
*Select Spring Size Below*