Armory of Iroas is a uncommon Artifact — Equipment card from Journey into Nyx (JOU), collector number 158. Current market price: $0.23 (foil $0.69), TCGplayer market prices via Scryfall.
Whenever equipped creature attacks, put a +1/+1 counter on it. Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)