This valve adopts a pillar type spring seal structure with board connection. It is a basic element for changing air flow direction in pneumatic system. Single electric control valve switches main valve by electric signal, and resets after power-off; while double electric control valve is a directional control valve with memory function and electric signal changes main valve. The main valve will not reset after the electric signal disappears and only reset after receipt of another signal. Inside nominal diameter: 6~25 Work pressure: 0.2~0.8MPa Medium temperature: -5~50 Celsius degree