This product is a lot of 5 replacement 58Wh MR90Y batteries designed for Dell laptops, including models such as 3421, 5421, 3721, and 3737. The batteries are black in color and are made with lithium-ion technology, offering a capacity of 5200mAh and a voltage of 11.1V. They are compatible with various Dell Inspiron and Latitude models and are an unbranded/generic product. It is important to note that the batteries may contain materials that could be potentially harmful, as indicated by the California Prop 65 warning. Made in China, these batteries are a reliable choice for keeping your laptop powered up and ready for use.