NF moduls are flow control for sping return and double acting actuators NF1 (Namur 1/4'') and NF4 (Namur 1/2'') is a single unidirectional needle valve for spring return and double acting actuators NF2 (Namur 1/4'') and NF5 (Namur 1/2'') is a double unidirectional needle valve for double acting actuators NF3 (Namur 1/4'') and NF6 (Namur 1/2'') is a double unidirectional needle valve for spring return actuators