One is advertised as a standard ratchet (2426) while the other is the heavy duty ratchet (2492); the 2492 is slightly bigger in dimension and "
...superior in strength and durability".
2426 - 4-3/4" overall length, 25/32" head diameter, 3/4" swing arc
2492 - 5-1/4" overall length, 1-5/64" head diameter, 1" swing arc
Gathered from the catalog page:
Image sourced from Royal Supply