The ILLINOIS CAPACITOR/CORNELL DUBILIER RJD2450ST1 is a rechargeable LI-ION coin cell battery with a voltage of 3.7VDC and a capacity of 200mAh. This battery has a compact size, measuring 24.5mm in diameter and 5.4mm in thickness, making it ideal for applications where space is limited. The battery also features leads for easy installation and connectivity. With its high energy density and long cycle life, the RJD2450ST1 is a reliable power source for various electronic devices and equipment.