Symbols of Duty 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, Symbols of Duty is Unlimited.
YGOPRODeck lists Symbols of Duty for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Symbols of Duty appears in Legendary Decks II (LDK2-ENJ33) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Symbols of Duty is about $0.05 on Cardmarket (prices change frequently).
