1. trailer part 2. 50mm, 1-7/8, 2" etc 3. 2 holes, ... , electric brake 4. steel, SG iron Trailer part, we produce and supply various of trailer parts. It includes trailer couplings, rollers, rollers holders, various ... the world, we are leading manufacturer and exporter of trailer parts in China, DD Machinery are ready to service you, thanks. trailer part