Tembo Trunks TTGrey Portable MP3 Player Headphone Speaker Amplifiers, Grey (Pair)

These don't really do much. Maybe add a little to the mid range, but you're still better off just using the speaker on your phone. I got them for 6 bucks, but they aren't even worth that. Also, they smell pretty bad.

I could not get them to work. I noticed that they specified iPhone headphones but can't imagine how they might differ from the 4 different styles of in ear headphones I tried them with.

I mean I guess they work to some extent but they are not speakers and they are not amplifiers...they are rubber cones that the earplugs slide into and if you crank the volume you can sort of pretend they are speakers.

Absolutely worthless. They make a barely noticeable difference and are huge. you're much better off getting something else. Don't waste your money like I did.