Sorry for the late reply.
We have 3 size options…
small = 4” x 7”
medium = 5” x 8”
large = 6” x 9”
It is important that you have the correct size as too large can be very cumbersome.
The heat is directed to the inside with an insulated layer to prevent it from radiating outwards.
For me the highest setting gets too hot very fast and I need to step it down a level to medium.
Regarding the instructions… this needs to be updated to 5 minutes for preheating or even skipped altogether as the temp will be hot enough while wearing in no time…