309 1.55v Silver Oxide coin cell / watch battery
Blister Packed (single)
Will also replace other coin / button / WATCH batteries:
309 V309 10 L 13 D309 7 SR 754 SW R 309 16 RW 38 SR 48
Battery Type: Silver Oxide
Battery Voltage: 1.55 V
Battery size: 7.9mm x 5.4mm