A directional control valve includes: a base and a slider longitudinally movable relative to the base. The base includes: a rectangular body having a longitudinal bore, a transverse bore, and a chamber formed at an intersection between the bores; supply and function seal plates, each having a stinger disposed in the transverse bore, one or more receptacles, and a passage extending from each receptacle through the stinger; and a supply, first function, and second function blocks, each fastened to the body and having a stinger disposed in the respective receptacle and a coupling for connection to a flow line. The slider includes: a sliding seal assembly disposed in the chamber; and an operating rod fastened to the seal assembly.