Alkaline batteries
		I wouldn't recommend alkaline batteries for the F2 because they often leak out corrosive liquids even when their power output is still good. I would recommend 3V lithium batteries, as I have never heard or found them leaked. If you use alkaline or silver oxide batteries, then regularly check they are not leaking or sweating.
		Even branded batteries leak These batteries were still producing 1.477V and passed the DP-1/11 battery check
		Battery liquids seeped into the battery contact and tag			The battery tag was corroded and full power could not get to the finder