As shown in the pneumatic symbol below, the Shuttle Air Valve has three connecting ports: two pressure ports (P1 & P2), one on each end of the valve, and an outlet port (A) on the top of the valve. An internal check valve piston moves freely between the two ends of the valve. When air pressure is applied to one of the pressure ports (e.g., P1), it pushes the piston towards the opposite end of the valve. This prevents the air from exiting through the opposite pressure port (e.g., P2), but allows air to flow through the outlet port (A). The Shuttle Air Valve is designed to allow two different air pressure sources (P1 & P2) to be alternately shuttled to a single outlet (A), while preventing backflow from one pressure source to the other.

Shuttle Valve (Units in mm)
Part No.	G (NPT)	A	B	C	D	E	F	Cv
ST N1/8	1/8	40	24	16	4.5	25	21	0.35
ST N1/4	1/4	50	35	22	5.5	35	25	1
ST N3/8	3/8	75	48	30	7	50	42	2
ST N1/2	1/2	75	48	30	7	50	42	3.5
ST N3/4	3/4	110	72	40	7	70	58	6
ST N1	1	110	72	40	7	70	58	10