What is the difference between a 7490 and a 7493?

• 7490 is a MOD-10, 7493 is a MOD-16
• 7490 is a MOD-16, 7493 is a MOD-10
• 7490 is a MOD-12, 7493 is a MOD-16
• 7490 is a MOD-10, 7493 is a MOD-12