NOTE: Suunto recommends that the battery cover and the O ring are changed simultaneously with the battery to ensure that the unit remains clean and water resistant. Careless battery replacement may void warranty.
Make sure that you have purchased original Suunto battery kit (including battery and battery lid with O-ring installed) in order not to void warranty
In case you choose to buy batteries only (not complete original battery kit) the battery model is 2032.
When not using original Suunto battery kit we can not guarantee promised battery lifetime. Batteries that we in this case recommend are manufactured by Energizer and Sanyo