This part of ISO 4254, where used with ISO 4254-1, specifies the safety requirements and their verification for the design and construction of rotary disc mowers, rotary drum mowers, as used for forage crop harvesting in agriculture only, and flail mowers with a horizontal axis for use in agriculture only, that are mounted, semi-mounted, trailed or self-propelled. It describes methods for the elimination or reduction of hazards arising from the intended use and reasonably foreseeable misuse of these machines by one person (the operator) in the course of normal operation and service. In addition, it specifies the type of information on safe working practices to be provided by the manufacturer. Flail mowers with a horizontal axis that can be opened at the rear only for maintenance reasons are included. This part of ISO 4254 is also applicable to mowers equipped with a conditioning device. This part of ISO 4254 is applicable only to mowers intended to work at ground level, examples of which are given in A.1.