This is a 3V Laser Lithium Manganese Dioxide Battery.
This lithium battery is used in control systems and other electronics applications and is a high-capacity cylindrical lithium battery with a bobbin structure and laser-sealing. The CR12600SE CR2NP uses Lithium Manganese Dioxide chemistry for high energy density. Self discharge is low at less than 0.5% per annum at 20??C, giving an effective shelf life of 10 years.