Gavel of the Righteous
From New Capenna Commander set
Gavel of the Righteous
Artifact — Equipment
At the beginning of combat on your turn, put a charge counter on this Equipment.
Equipped creature gets +1/+1 for each counter on this Equipment.
As long as this Equipment has four or more counters on it, equipped creature has double strike.
Equip—Pay
or remove a counter from this Equipment.