Being int he Southwest, we've become big fans of MSR's Hydration kit - a simple set up that enables any of their Dromedary bags to be converted into a bladder. The on-off valve is solid and works reliably and the bite valve is not prone to leak.
Includes-MSR Bite Valve and shut off valve
42-inch taste free polyethylene-lined drinking tube that resists freezing
Custom Hydration cap with 360-degree swivel elbow
Adaptor to fit new 2016 Dromedary and Dromlite Bags
Lifetime Manufacturer’s Warranty/Made in USA of US and Imported Materials