What this is Replacement Liion battery for Dyson DC31 (Type A). 4000 mAh capacity, 22.2 V. Key benefits — why you need it Restores vacuum runtime and performance when your original DC31 battery is worn or no longer holds charge. No memory effect: can be charged or discharged as needed without reducing capacity over time. Builtin protections and certifications improve reliability and safety during regular use. Main features Capacity and chemistry: 4000 mAh, 22.2 V lithiumion for consistent power output. Manufacturing: lead SMT process to meet environmental standards. Safety: CE, FCC, and RoHS certified. Integrated protection against overcharge, overdischarge, overcurrent, and shortcircuit. Durability: designed for repeated charge/discharge cycles without significant capacity loss. Compatibility and installation notes Compatible with Type A batteries for Dyson models: DC31, DC34, DC35, DC44, and DC45. Not compatible with DC31 Type B models. Please check the connector on your original battery before . Not fit all Type B models, including certain MK2 variants (e.g., DC31, DC35, DC44 MK2). Confirm model and connector type to ensure fit. Practical use scenarios 1. a degraded DC31 battery to restore original runtime and maintain cleaning efficiency in a typical household with pets or heavy foot traffic. 2. Keep a spare Type A battery on hand for extended cleaning sessions in larger homes or multilevel residences to avoid interruptions while recharging. 3. Swap in this battery when preparing a refurbished or secondhand Dyson DC31/DC34/DC35/DC44/DC45 to ensure reliable performance for resale or continued use. Additional notes Verify the connector type and model designation on your vacuum before ordering to avoid compatibility issues. Designed as a direct replacement for the specified Type A models; do not use if your unit requires a Type B or MK2 variant.