Used 36v batteries. Original from Bosch and they hold a charge. Price is for 2 batteries.
IKRA BOSCH 36V IB-LM 33 Lawnmower, surfaces up to 250 m², cutting width 33 cm, cutting height 30-70 mm without battery 36V 2 Ah & charger
Bosch cordless, powerful lawnmower AdvancedRotak 36V-40-650 (for mowing the lawn; 36V system; Cutting width: 40 cm; tool kit, with battery and charger)
Flymo 36V EasiStore 340R Cordless Lawnmower Mower 34cm Twin 18v / 36v Bare Bosch
Bosch ADVANCEDROTAK 36V-44-750 36v Cordless Rotary Lawnmower 440mm No Batteries
Bosch Garden Advanced Rotak 36v Cordless Lawn Mower 36V-44-750 Baretool
Bosch ADVANCEDROTAK 36V-44-750 36v Cordless Rotary Lawnmower 440mm 2 x 6ah Li-io
