My only advice would be to not buy online without testing the cord somewhere physically if you can help it.
I picked up two of these
http://www.amazon.ca/gp/product/B00N...ilpage_o02_s00
Based on the price and rating, and neither one works without monkeying around with the connection. I suppose you get what you pay for.
(I love my Sleephones too, BTW
)