If you’re looking for one, that appears to be a 1940s Lightning Portable Adding Machine with a Bakelite surface. Sometimes just called a Lightning Adding Machine.
This one in particular is one of the later 50s models that does direct subtraction. The earlier ones don’t have the updated mechanism and you have to clear the unit to switch between subtraction and addition which makes them less useful for this.
If you’re looking for one, that appears to be a 1940s Lightning Portable Adding Machine with a Bakelite surface. Sometimes just called a Lightning Adding Machine.
This one in particular is one of the later 50s models that does direct subtraction. The earlier ones don’t have the updated mechanism and you have to clear the unit to switch between subtraction and addition which makes them less useful for this.