If you need a low profile hydration unit that can be mounted on or off armor, then the Thermobak AB is definately worth checking out. The design appears to be a mix of older Thermobak designs and the Armorbak to result in something along the lines of an Armorbak with shoulder straps.
The shoulder straps are full-on including a sternum strap making it a solid ride when directly worn on a person. There is good attention to detail where D-rings and the slack management system is even integrated in the main webbing straps. When it is desired to be mounted on a vest, the backpack straps can be tucked into the back sleeve and the lower connection points also have pockets on the lower back to be stowed in. 4 Webbing loops with slick-clips on the sides offer easy attachment to PALS webbing along with 2 repair SRBs along the upper middle. Like on the Armorbak, the repair buckle strap allows cinching down to create pressure. Note these straps are hidden under the flap on my main exterior picture. This flap uses a zipper and velcro seal system giving a fairly smooth opening with coverage security. On the upper portion is a 1" strip of loop velcro for name tape mounting and a substantial webbing loop is up top for hanging or to use as a handle. On the lower front of the exterior is even some PALS webbing (3x3) to allow mounting of a small pouch or 2.
The OMEGA Water Beast 102oz Reservoir is included and fits in a crafty manner allowing the majority of the bladder to be covered, but the main opening is accessable under the flap. An adjustable webbing loop is even up top to secure the bladder on. The Big Bite valve and Hydrolink valve cover are fortunately included in the package. Most users will route the main tube through the upper left or right shoulder ports, however the lower sides of the carrier have additional port holes for more options. There is even a zipper down the side for quick internal access whether it be to adjust the bladder or toss in some scoobie snacks.
Overall I find the Thermobak AB to be well thought out and a great example of usage versatility.
STATS: 102 oz (3.1 L) capacity or 189 CU IN (3.1 L) cargo