IEC 60335-2-91:2008 deals with the safety of electric powered walk-behind and hand-held lawn trimmers and lawn edge trimmers, with cutting element(s) of non metallic filament line or freely pivoting non metallic cutter(s), with a kinetic energy of not more than 10 J each, used by a standing operator for cutting grass, their rated voltage being not more than 250 V for a.c. or 50 V d.c.. Main changes in this edition include the revised endurance test in Clause 18; Annex B, which allows for battery-powered trimmers; and addition of informative Annexes BB, CC and EE on vibration, noise and safety instructions.