... ), specialized in all kinds of pneumatically (air/vacuum) foot brake valve, relay valve, air dryer, clutch servo, trailer valve, unloader valve, protection valve, etc.., which applied to heavy trucks, ... ), specialized in all kinds of pneumatically (air/vacuum) foot brake valve, relay valve, air dryer, clutch servo, trailer valve, unloader valve, protection valve, etc.., which applied to heavy trucks, ...