This shield holds 2 charges.

If are attacked with a spell attack that targets only you and you succeed the saving throw/the attack misses, you can use your reaction to expend 1 charge of this shield. You cannot expend a charge when hit with a spell that targets multiple people (Fireball, Lighting Bolt, etc.). 

If the spell attack requires a saving throw to take half damage, you reduce the damage you take by half once more, and you can reflect the spell back towards any target within 60 feet of you that you can see. The reflected spell uses your spell save DC if you have one, and if you don't the DC = 16.

If the spell attack is an attack roll, you instead divert the full force of said spell towards your target. Make an attack roll using your spell attack modifier if you have one, and if you don't the spell attack modifier = +8. 

You can choose to expend 2 charges when using your reaction. In doing so, the spell save DC and spell attack modifier increase by 1, and the damage reflected off the shield is doubled. 

This shield recharges 1 expended charge every other day at dawn. 

Shields require the Utilize action to Don or Doff. You gain the Armor Class benefit of a Shield only if you have training with it.