Staff of Defense

+1 Armor Class. The staff has 10 charges, which
are used to fuel the spells within it.
With the staff in hand, you can use your action
to cast one of the following spells from the staff:
mage armor (1 charge) or shield (2 charges).
No components are required.
The staff regains 1d6 + 4 expended charges
each day at dawn.
If you expend the staff's last charge, roll a d20.
On a 1, the staff shatters and is destroyed.