Ring of Shocking Touch

Electrical sparks surround this ring.
Ring has 3 charges. Recharges 1 charge/long rest or
when wielder takes 20 lightning damage.
* Unarmed punch for extra 1d4 electrical damage,
once per round.
* Spend 1-3 charges to do an additional 1d6 electrical damage per charge. Decide after hitting
but before rolling damage.
* Reaction and 2 charges to gain Resistance to electricity (choose before rolling saves or damage).
* Can cast Prestidigitation electrical effects.