I am struggling with the cap

We engineered the cap to be functional and added some simple instructions to the "bridge" that connects it to the mouth piece.

1 - From the closed position, you can press this bridge to pop the cap open, allowing for one handed operation.

2 - This bridge also has a slit down the center, which allows it to be clipped over the fin on the dial to hold it out of the way.

If the cap is too cumbersome, you can simply cut it off with a pair of sharp scissors.