Metalsilver Armor is a Equip Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Metalsilver Armor is Unlimited.
YGOPRODeck lists Metalsilver Armor for these formats: GOAT, OCG GOAT, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Metalsilver Armor appears in Dark Revelation Volume 1 (DR1-EN092) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Metalsilver Armor is about $0.03 on Cardmarket (prices change frequently).
