... 3A100, 3A200, 3A300 Series) 3 Port Air Operated Valve (3A100, 3A200, 3A300 Series)* 3A110, 3A120(N. O. ), 3A120(N. C. ), series air operated valve. * ... , 1/8".* 3A210, 3A220(N. O. ), 3A220(N. C. ), series air operated valve. * Exterior control, 3 port 2 position. * Port size ... ", 1/4".* 3A310, 3A320(N. O. ), 3A320(N. C. ), series air operated valve. * Exterior control, 3 port 2 position. * Port size ...