Ring of Thunder Striking

When worn by a Monk with Ki Empowered
Strikes, this ring gathers momentum and
unleashes it in a cacophonous strike.
It gains 1 charge when a successful Unarmed
Strike is made, up to a maximum of 10 charges.
Once charged in this way, a Monk may expend
all 10 charges after making a successful Unarmed
Strike attack, adding 2dX Thunder damage to the damage roll, where X is the Monk's current
damage dice for their Martial Arts class feature.