How to connect headphones to amp

Hi my friend is looking for one of those adapters so he can use his headphones connected to a amp. I have one of them my self but I have no clue what it is called. Its like a bigger audio jack. If anybody knows what its called feel free to post it.

I think this is it
http://www.music123.com/Hosa-Headpho...e-i18767.music

It would be a 1/8" to 1/4" headphone adapter. What you've listed a link for is an extension cord for headphones that are already 1/4" with a gender changer, not the adapter you're looking for. Anyway the headphone adapter can easily be found at Walmart, Kmart, or Radio Shack. It's too small an item to be worth paying the shipping for.

Some Best Buy's have them too. Haha. But Radio Shack will be your best bet.

thanks for the replies ill tell my friend about it.