This document provides basic requirements for gearboxes to operate industrial valves for manual and automated on/off and modulating duties, this includes manual override gearboxes. It includes guidelines for classification, design and methods for conformity assessment. It does not cover gear systems which are integral part in the design of valves and subsea gearboxes. Other requirements or conditions of use different from those indicated in this document should be agreed between the purchaser and the manufacturer or supplier (first party), prior to order.