I have the M.U.L.E. I got 10 years ago when stationed at Ft Irwin CA. (Mojave Desert). Biking at 125F puts a hurtin on ya if your not ready for it. That and my heat tolerance is way low from 9 years in AK, I still can't handle anything over 70F without sweating. So carring 2 LG bottles and the 3L CamelBak is my only option

I also store small daily goodies in the pack, I don't have much in bike bags yet and this keep all my importand items on me when I get off the bike.