I'll chime in since I'm using one of these marsupial water bottle holders right now. I'd been hanging my water bottle off my bino harness by a carabiner before so this is a big step up. I was worried it wouldn't work out at first because it looked like it would be too short - I have one of the taller hydroflasks at 11" - but the bungee that grabs the water bottle does a great job of holding on. I'm running this in a chest rig set up attached to my small marsupial bino harness, which has been great.