... ,9522002210 4522002110 Cast iron / aluminium Trailer Air brake coupling head for full trailer, tractor (1). ... is with black rubber seal in it,to reinforce the safety of the air brake system,it ... fix.(3).Use to connect the air brake system of the heavy truck,semi-trailer,full ... so on ,welcome to contact with me and visit our company ! trailer brake coupling pamp coupling,air brake system ,brake valve