DrinkLink Hydration Tube System with 1.5L Shades - Translucent Blue
You can see right in the picture that the area were you screw the cap on has groves. I thought since it is translucent, that l was just seeing the groves for the cap, and that the outer part which the rest of the bottle is laminated to would be one continuous smooth area. It is actually four different 16th" groves spaced about a 16th" apart, instead of being a half inch smooth surface to laminate the plastic to. Made to fail and fail it did after 3 uses, even though l made a special cradle for it so it wouldn't move around in my hydration pack, and protected the hose from getting damaged. I would not just put it in a hydration pack without protecting the water line, or I'm sure it would fail the first usage. Pour design.