Replacement battery for vacuum cleaners. Compatible replacement battery, not an original battery from the manufacturer! Refer to the device and battery numbers listed to select the right battery for your device! Replacement battery suitable for: Deik: MT820 Identical to the following batteries: Please note: Opening your device voids the warranty. Installing this battery is especially complex and follows at your own risk. We do not assume any liability for damage and failure with devices and/or batteries.