This DELL Precision Workstation M40 Series Special Offer Battery Pack is 100% compatable with the 08M815 DELL Precision Workstation M40 Series Special Offer Battery Pack. Our batteries and accessories are made with high quality parts and are guaranteed to meet or exceed the original equipment manufacturers specifications at a reduced price. All batteries are tested for 100% quality control assurance. This DELL Precision Workstation M40 Series Special Offer Battery Pack includes a warranty to guarantee that it has no manufacturing defects.