Excellent for winter cycling, fits all Wide Mouth HydroFlask bottles. I got it for the 354 ml mug that fits into bottle cages and into smaller frames that don't have space for the HydroFlask sport bottle. Haven't had any freezing issues with this cap even at -15 C, and the heat loss compared to closed caps seems minimal. Also, all the other caps come with the handle that is annoying on a bike and doesn't leave a very clean look when cut off.
Verified buyer
