REAR TOPEAK BEAM II MTX V TYPE BLACK Home [blog.corporacionbi.com]. The newly designed, extended, and widened version of the MTX BEAMRACK is better suited for 29 MTB and gravel bikes Available in 3 formats, A Type for XS and S frames, E Type for Medium frames, and V Type for larger frames Features an MTX QuickTrack panel, compatible with MTX 1. 0 and 2. 0 system bags and baskets Rear light mount is compatible with a variety of light styles and sizes Integrated rubber bungee cable helps secure loose cargo