Li-Ion 18V
From Amazon
Einhell Power X-Change 18V, 3.0Ah Lithium-Ion Battery Twin Charger Starter Kit - 2 x 3.0Ah Batteries and Twincharger Set - Universally Compatible With All Einhell PXC Power Tools And Garden Machines
Wickes
Einhell Power X-Change 3.0Ah Battery Starter Kit
This product is also available at 4 unverified merchants.