BRAND: USPECIAL Model: D216005 VDC: 21V CAPACITY: 6000mAh RATE: 5C POWER: 600W CELL: 15 Battery SIZE: 125*75*79mm BRAND: USPECIAL Model: D216010 VDC: 21V CAPACITY: 6000mAh RATE: 10C POWER: 1200W CELL: 15 Battery SIZE: 125*75*79mm Our building li ion battery packs are designed and built to be used in conjunction with the appropriate power tools and interchangeable with the Dayi replacement battery pack.