2x Masione Neato XV-11 XV-12 XV-15 XV-21 Signature Pro Robotics Replacement Battery 7.2V 3500mAh Battery Type: NI-MH / Voltage: 7.2V / Capacity: 3500mAh It works just like your original battery and it can be charged by the original charger Fully compatible with your vacuum cleaner, give you an amazing using experience Easy to charge and connect, compatible with Neato Robotic XV-21 Brand-new product with 1 year warranty