I have never heard of this box heater before.

It appears from Canoedog's photo that it is just a hollow unit (think coffee can) with a holes, slots in the base to anchor it and a bail handle. The 'can' absorbs heat from the open flame and radiates it outward, or the top can be used for cooking.

Is this a reasonable description?

Sue

p.s. I am looking at 'box heater' at eBay. What does 'catalytic' mean in this sense? What does it do?