US $19.99Buy It Now
US $49.99 MSRP
http://m.ebay.com/itm?itemId=351097352805
Thanks OP. Was about to buy one but then saw this review on Amazon:
I got one of these packs with some rewards points that I had, and the bite valve leaked from the start. It is totally useless unless I want to take it on a run and have it cool me off by slowly leaking water on me.