These are covers for the AC blades on USA AC chargers. Use these to cover the charger plug when in your bag or suitcase to prevent damage to the charger plug or to other items in your bag. The 2-prong plug cover is designed to mate with an iPhone 5 watt charger, and the 3-prong cover will mate with any 3-prong AC USA plug.
Credits:
SteveGlenner