Opaline Bracers is a common Artifact — Equipment card from Fifth Dawn (5DN), collector number 141. Current market price: $0.16 (foil $2.79), TCGplayer market prices via Scryfall.
Sunburst (This artifact enters with a charge counter on it for each color of mana spent to cast it.) Equipped creature gets +X/+X, where X is the number of charge counters on this Equipment. Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)