This EH series is interchangeable with STUCCHI VR SERIES, FASTER FLV SERIES, VOSWINKEL RH SERIES, VOSWINKEL RK SERIES, and DNP PRH3 SERIES. Steel Product. The 64 Series German Screw Coupler features a low-leakage valve for sealing and threaded connections, enabling secure mating even under residual pressure. Its robust construction makes it ideal for demanding applications, including mobile construction and industrial hydraulics.