Manual and mechanical forces quoted are at 6.3 bar

The 3/2 Poppet Valve ZNCN/666, ZS/666 and ZS/667 ranges are 'normally closed' and 'normally open' respectively. They are externally identical. 

These valves are particularly suitable for the pilot operation of the larger control valves and their compact size enables them to be built into machines and fixtures very easily. Many of these valves can be panel mounted and can be supplied with legend plates. 

These models, 3/2 Poppet Valves ZNCN/666, ZS/666 & ZS/667, can also be used as 2/2 valves. In this case the main air or oil supply must be connected to the 'inlet' port. The exhaust port should be plugged. Manual/mechanical operating forces quoted relate to mains air supply pressure of 6.3 bar.