Chris Williams wrote a review of CamelBak Flow Meter on February 13, 2013
Familiarity: I gave it as a gift, but have feedback to share
I bought this as a gift for my girlfriends Camelbak who i just got into hiking and so far it seams to work great so great that it seams to have a problem turning off it is supposed to have a sleep timer on it that takes effect after 24 hours of no use i cant seam to get it to turn off so i have been just popping the battery out when its not being used since it is very easy to set up. She enjoys it very much and finds its very easy to use with out her even reading the instructions.
It's not the most amazing thing out there but its $29.95 and sometimes you can find it even cheaper then that for the money its a very cool add on.