An 18th century antique treen tinder box with steel and flint.
note the divided interior with the build up of carbon to the interior.
These antique treen tinder boxes were rarely made in wood. They have a divided interior one for storage of the flint, steel etc and the other known as the hearth. This is where the flint would be rubbed against the steel to create sparks to light either bits of material or wood. This would then be used to light the candles and fires. There would be a damper lid or cloth which would then be used to extinguish any sparks, hence why wood was not a great choice of material.