This routes the hub gear cable through a 90 degree bend just before attachment to the gear indicator chain. A bit about the Brompton hub gear pulley assembly The Brompton gear cable pulley assembly is part of the hub-gear system used on the majority of Bromptons. It's job is to help route the gear cable through approx 90 degrees where cable emerges from the cable outer and connects to the cable anchor (which in turn connects to the gear indicator chain). In (approx July) 2015 the design changed slightly to a slightly more rounded shape. This is compatible with older Bromptons (long and short wheelbase, SRAM and Sturmey Archer Hubs) - just the design has changed slightly. Made of tough plastic, it contains a wheels which allows the cable to move freely. Brompton Q part code: QCPULA Brompton