Need a battery for Dell Laptops/Notebooks with the following model numbers: Studio XPS 16, 1640, 1645, 1647 (9-cells)? BTI has you covered with our premium 9 cell LiIon battery. This product has been engineered to meet or exceed the original manufacturer's specifications and replaces the original Dell part numbers 312-0815, 0W296C, W303C, X411C. All BTI batteries are manufactured and tested under our stringent quality standards and come with an industry leading 18 month manufacturer's warranty. BTI... True to the original.