Bio Tru may be a fairly new product. It was recommended by my optician and my eye doctor, who also uses it. It is not a perscription product. I only use contacts when snorkeling, so I don't need a quart bottle, lol. 4oz is not much more than 3.4oz. I still have a couple of months (darn it) to try and fiqure this out. We are going down for three weeks this trip. Can't wait. <img src="http://www.traveltalkonline.com/forums/images/graemlins/Grin.gif" alt="" />