Brand: RadioShack. MPN: 273-1049. *With the help of the Adaptaplug series you can plug your AC or DC powered electronics (wireless phone mp3 player etc.) directly into a standard socket. Check your device for plug size. *Adaptaplug O conversion size: O.D.: 5.5mm. I.D.: 2.8mm. *This plug mates with Enercell/RadioShack branded DC and AC adapters - allows end user to select the best tip for their device and select the proper polarity.