Two or Four x "Smart Finder GPS Tracker" Units, comes complete with CR2032 Lithium Ion Battery each — absolute-magic.com - Find almost anything but the ordinary!
Amazon.com: HQRP 4-Pack CR2032 CR2O32 Lithium Battery Compatible with IHome IP21 Alarm Clock : Home & Kitchen
Amazon.com: Energizer 4 CR2032 2032 Battery Watch/Electronic 3v 3 Volt Lithium Button Cell Batteries : Health & Household