Biotrue is from Bausch & Lomb, and I believe it's intended to replace Renu, their older product. I still use Renu, and it is available in 2 ounce (60 ml) containers. Each container that size lasts a week or more for me.

Dan <img src="http://www.traveltalkonline.com/forums/images/graemlins/Cheers.gif" alt="" />