A robust design that can withstand continuous service in workboat and high-performance applications on: luxury motor yachts; sport fishing boats; express cruisers. The ZF 325 1-A is a reverse reduction marine gearbox with hydraulically operated multi-plate clutches compatible with all types of engines and propulsion systems, including waterjets. Among its main components we find: the light and, at the same time, robust aluminium alloy casing that allows it to resist sea water; precision case-hardened and ground gear teeth thanks to which longer life and smooth operation can be achieved; the ZF 325-1A output shaft thrust bearing which allows the maximum forward and backward thrust of the propeller to be supported; the smooth and reliable hydraulic change integrated with a control lever that allows the connection of the push-pull cable; the replaceable oil filter cartridge; a compact and space-saving design thanks to the 7° downward angle inclination and the Beveloid gear; the “SUPERSHIFT” clutch control. It is suitable for installations with two motors, when they have the same ratio and torque capacity in forward or reverse mode. Its design, manufacturing and quality control standards comply with ISO 9001.