The CR2025 lithium cell, like any lithium coin cell, is rated at 3.0V. The four digits in the battery designation actually give the dimensions of the coin cell. The first two digits, 20, mean that the coin cell is 20mm in diameter. The last two digits, 25, mean that the CR2025 cell is exactly 2.5mm high. Lithium is the name of a metal used in the manufacture of the CR2025 lithium battery.