Champion's Helm is a special Artifact — Equipment card from Kaladesh Inventions (MPS), collector number 7. Current market price: — (foil $68.97), TCGplayer market prices via Scryfall.
Equipped creature gets +2/+2. As long as equipped creature is legendary, it has hexproof. (It can't be the target of spells or abilities your opponents control.) Equip {1}