Shining Armor is a common Artifact — Equipment card from The List (PLST), collector number ELD-29. Current market price: $0.34, TCGplayer market prices via Scryfall.
Flash When this Equipment enters, attach it to target Knight you control. Equipped creature gets +0/+2 and has vigilance. Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)