Subaru Key Fod Battery Type
If you have a 2010 Subaru Legacy, right about now you may encounter issues unlocking the door with the key remote. This is because the battery in the key fob is dead. Looks like the life of the battery is 6 years.
There's no need to go to the dealer to get it fixed. You can find instructions on replacing the battery on iFixit. It very easy to open the Fob and replace the battery.
The Key fob for the 2010 Subaru Legacy uses the Panasonic CR-1620 (3V). This is a not a common battery and is not available at CVS or Walgreens. You can find it at Battery Plus, or on Amazon.com.
This is what the Key Fod looks like when taken apart.
Amazon Purchase Update - October 21, 2016
I purchased the Energizer CD1620 Lithium Battery from Amazon. It as a five pack and it worked perfectly. There's no "freshness" date on the pack, so I don't know how long they will last, but for $6.83 it was a good a good deal for 5 batteries. I need the batteries for both my key fods.