Sorry, currently out of stock
The temperature indicating cap is what makes the Dynavap magic. This is the same cap that is included with every model, if you have lost your cap or otherwise need a replacement this is what you need.
My Dynavap M lost its heating click. Only had the M for a few months. Rather than claim a defect. I ordered 2 new caps. 2 days and they were in my mailbox. Nice!