You must have an Endorsement A specified on your licence to operate a vehicle equipped with an air brake system. The endorsement is not required when operating a Class 3 or 5 vehicle licensed as a farm truck or trucks with air over hydraulic brakes.
2 Way Quick Release Valve - Yong Sheng Auto
SGI – Vertex Safety
TTP Quick Release Valve, # TTPBW289714
Air Quick Release Valves, 2. Air Valves
Relay valve - SGI
Air Brake Quick Release Valve
SGI looking to help you avoid smelly problem - DiscoverHumboldt
MJAbbott Direct - 40mm (1½'') Saunders A040 BSPP SGI RHI Q cast
Mini Flow C10 Valve - Special Gas Instruments - SGI