Brompton Chain Tensioner Version Derailleur 2 and 6-speed

This chain tensioner is for Brompton folding bikes with 2 speed, 6 speed SRAM or 6 speed Sturmey Archer / BWR (Brompton Wide Ratio) hub gears.

This works as a chain tensioner (keeps the chain taut while riding and folded) and as part of the Brompton designed derailleur mechanism that can be moved from side to side to allow the chain to move between the two rear sprockets.