Two 13" Support Arms for Use with the CMP-485 Super Clamp Assembly On the APEX AX-48 Pro Keyboard StandTBR-130 Tribar arms are support arms that hook into a CMP-485 Super Clamp (sold separately). When used together, Tribar arms and a Super Clamp form one APEX tier to be used on an APEX AX-48 Pro keyboard stand. Total load capacity is not to exceed 250 lbs. and only two tiers are encouraged. The TBR-130 Tribar arms are 13" in depth and are intended to support mid- to small-sized keyboards. Also available are TBR-180 18" Tribar arms for use with deeper, larger keyboards, synths, and workstations.Ultimate Stand(s) Using this Part: CMP-485 Super Clamp AX-48B AX-48S AX-48 Plus AX-48 Pro (black and Silver) AX-49 Pro Plus TBR-130 Features: Extraordinarily strong tier support arms For use with Ultimate Support CMP-485 Super Clamp (sold separately) To be used on an Ultimate Support APEX AX-48 Pro keyboard stand 13" Tribar arms for supporting mid- to small-sized keyboards Specs: Sold In: Pairs (Quantity 2) Length: 13" (457mm) Load Capacity (with CMP-485): 125 lbs. (57 kg) Weight: .9 lbs. (.41 kg)