Abstract: Spool valve for fluid systems, the valve having a slidable spool in a bore in a valve block having three ports spaced aially along the bore for control of fluid flow, the spool having three spaced O-ring seals to correspond with the ports and having a reduced diameter portion between two of the O-ring seals, and a pressure-equalizing conduit connecting one end of the spool with the outlet port of the valve. Small lands of substantially equal diameter to the spool adjacent the reduced diameter portion before the two O-ring seals provides restricted or throttled fluid flow prior to increased fluid flow via reduced diameter portion.