Amazon.com Product Description:
The PodDuo is designed to connect two mini-stereo headphones or speakers to the same jack on your iPod, portable cassette, CD or MP3 player. Now you can share the music on your iPod like two people sipping a drink with their own straw. Or, you can connect two powered speaker systems to a single iPod. The t-shaped adapter features a single male 3.5 mm headphone adapter and two female 3.5 mm jacks. At .4 ounces, the PodDuo is a virtually weightless addition to your iPod accessory kit.

What's in the Box
PodDuo t-adapter, user's manual.