This EH series is interchangeable with STUCCHI VEP-P SERIES, PARKER FET SERIES, FASTER FHV SERIES, VOSWINKEL FT SERIES, DIXON VEP SERIES, and DNP PST4 SERIES. Steel Product. Engineered for demanding hydraulic systems, the 299 Series provides reliable performance in applications subject to extreme pressure impulses and residual line pressures. The innovative thread-to-connect design significantly reduces wear and prevents brinelling, while the internal valve technology enables safe connection and disconnection even under high residual pressure conditions. This series is used in a high wind application environment, and the safety pin lock will ensure the couplers are physically stable enough to perform properly.