Ford Transit CUSTOM 2012+ onwards - this is the rubber seal strip which sits along the sill line for the left side loading door (Passenger in the UK).  This trim is supplied with all of the clips ready to clip straight into place on your Custom, it is black.  It is common for the clips to rip out of these seals and for them to scrunch up, this new seal will solve those issues.  The seal is brand new and a genuine Ford product.