Exc Ring n Pent From Mob

The game has no such thing as separate drop just for ring and pendant while ignoring the rest of the exec items. It's a global config and it's adjusted to our server rates.
Exec items from mobs may drop up to 3 exec options so obiously the chance should be low.

As for the rings/pends from boks they drop with up to 2 options but obviously you need patience in order to get the best items.

Rings/Pendants should be more rare than most of the items since you only need a pair of rings and a single pendant.