This new SIDE POCKET ECHO is an infinitely-adjustable insulated water bottle pocket. It will securely hold anything from a small 0.5 liter size, up to a huge 1.5 liter size. The pocket can be adjusted to exactly the size of any container in that range.
The SIDE POCKET ECHO takes the form of a neoprene sleeve that wraps around the water bottle and it secures with two clips on two straps. It makes for a perfect fit, regardless of the the size of the bottle, and it allows one-hand removal and replacement of the bottle.
NOTE 1: This side pocket will not mount on the CS2 or CS3 because these modules do not have FLEX Mount Side Pocket Stations. Only the CS4, CS5, and CS11 can accept Side Pockets.
NOTE 2: The clips on the SIDE POCKET ECHO are small and fragile. They certainly do not survive the kinds of pulling forces that can be applied to them if the user simply clips the loose strap together and then pulls on the end of the strap to adjust. The clips will snap immediately. If you're ginger when adjusting them, they'll last forever. If you yard on them, they'll just break.
We had to make decisions about the various tradeoffs that occur when selecting this buckle for the SIDE POCKET ECHO. Small and thin is certainly the most desirable because that helps keep it out of the way during daily life.
We did look at much bigger buckles, but the problem is that they are also much longer, by necessity. As a result, they cannot "fit" around the curve of a water bottle, especially a small water bottle and thus the clip ends up protruding away from the pocket and creating a different problem, and becomes an annoyance that will get in the way every single day that the bag is used.
We chose to stay with the small buckle because  if the user takes care when adjusting the length of the strap by using two hands and being sure to keep the forces low, then any necessary adjustment can easily be made. And  we know that this adjustment will likely only be made once to accommodate the desired container. After that the straps will likely not be touched, and the nice small out-of-the-way buckle is a real advantage.