Camelbak widemouth strapless cordura pouch w valved tube. I usually wear a backpack, so I just slip in the pouch. I used to use Camelbak backpacks, but prefer a bicycling backpack. If I am not on a bicycle, I use the minimalist Camelbak cordura pouch with straps.
In temperate zones, I do not need the cordura pouch, but in FL sun & heat, I appreciate the ice cubes and the insulation with every single sip.
I have used bladders for decades and the only brand that dependably works is Camelbak, with a valved tube.