pegasus wings vs. dragonclaw ring

[Grimbly]

Pegasus wing = +10 max energy for 450 credits
Dragonclaw ring = +5 max energy for 500 credits

What am i missing here? This game is sooo confusing on mobile.

[Admin]

The ring is not a shop item.

[kroger]

so it means you have to drop it on a boss before acquiring it.