Need a battery for Dell Laptops/Notebooks with the following model numbers: Studio XPS 13, X1340 (6-cells)? BTI has you covered with our premium 6 cell LiIon battery. This product has been engineered to meet or exceed the original manufacturer's specifications and replaces the original Dell part numbers 312-0773, 0P878C, P891C, T555C. 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.