This operator manual covers Hitachi Zaxis series excavators, including the 125US, 135US, 135USK, 225US, and 225USLC models. These diesel-powered machines feature hydrostatic transmissions and are engineered for robust performance in demanding applications. Specific model variations offer different engine displacements, power outputs, operating weights, and dimensions, catering to a range of project requirements. Notable safety features include a ROPS cab, backup alarm, travel alarm, and a safety lock lever, underscoring Hitachi's commitment to operational integrity and operator well-being. The purpose of this manual is to provide comprehensive guidance for the operation, maintenance, and servicing of your Hitachi Zaxis excavator. It details essential information such as engine specifications, hydraulic system capacities, and recommended service intervals for engine oil. Additionally, the manual outlines key operational capabilities like digging depth, reach, and bucket capacity, along with critical safety guidelines. This English-language resource is designed to assist owners, operators, and technicians in ensuring the longevity, efficiency, and safe operation of their equipment.