... ), 3A120(N. C. ), series air operated valve. * Exterior control, 3 port 2 position. * Port size: M5χ 0.8, 1/8".* 3A210 ... ), 3A220(N. C. ), series air operated valve. * Exterior control, 3 port 2 position. * Port size: 1/8", 1/4".* 3A310, 3A320(N ... (N. C. ), series air operated valve. * Exterior control, 3 port 2 position. * Port size: 1/4", 3/8". 3 Port Air Operated Valve (3A100, 200, 300 Series)