Coal Pouch

Any bundle (modded bundles too) in a module slot, without an amethyst shard in it.

The module screen with a coal pouch and a depth gauge: stored fuel and the pouch's worth below the slots

The orange bar on the right edge of the picture is the fuel gauge (see the Depth Gauge picture).

What it does

The CRT then eats only from the bundle, never from your inventory.
It eats anything that burns in a furnace, worth what it would burn there compared to coal: a coal block is 10 coals, a lava bucket 12.5 (you get the empty bucket back), sticks and saplings little. Small fuels are eaten in batches of about one coal's worth.
The CRT can store up to 256 coals' worth. Whatever doesn't fit stays in the bundle.
A thin bar beside the picture shows stored fuel plus the bundle (full at 64 coals). The tooltip shows both numbers.
While the pouch has fuel, the picture never dies.

It burns everything that burns, enchanted wooden tools too. Don't keep them in the pouch.

Put an amethyst shard into the pouch and it becomes a Finder Bundle instead; then it stops feeding the CRT.