Einhell 18 V 4-6 Ah Multi Ah Power X-Change PLUS (18 V, for all PXC devices, charge status display, active ABS battery management system, charging cycles adapted to situation, without charger) :
Einhell 10.8 V Li-spare battery 1.3 Ah (4511301) for RT-MG 10.8 Li : Amazon.nl: DIY & Tools