Batwarmer

Question
I am trying to get something definite on the use of bat warmers. With the high cost of composite bats and the possibility of breakage in cold weather it poses a problem. Not only for the cost of replacement but for safety as well. In the past our subs did their beat to keep the bats warm by holding them between their legs but were told they couldn't use their gloves with hand warmers. A simple blanket wrap doesn't do enough when the snow is blowing as it often does in the early March games. So what is the ruling? Can we use bat warmers with hand warmers thrown inside the warmer?

Response
The Pyroflite Batwarmer is the only bat warmer endorsed by USSSA at this time.