These tools are purpose to save time necessary when replacing valves in modern 16 to 20 valve heads.
KA-4183A Multi-Valve, Large Tool
Work on valves of 4-valve-per-cylinder heads (5.5mm valve stem diameter or larger with under 40 lbs. seat pressure)
KA-4183B Multi-Valve, Small Tool
Work on valves of 4 and 5 valve-per-cylinder heads (5mm valve stem diameter or smaller)