Describes all significant hazards, hazardous situations and events relevant to walk-behind trimmers, powered by a combustion engine, with cutting means using non-metallic filament line or freely pivoting non-metallic cutter(s), of which the cutting elements rely on centrifugal force to achieve cutting with the kinetic energy of a single cutting element not exceeding 10 J, designed for cutting grass or similar plant material, when they are used as intended and under conditions of misuse which are reasonably foreseeable by the manufacturer.