Depth Amulet is a Continuous Trap Card.
Trap Cards are normally Set first and can be activated on a later turn, often in response to an action.
On the current TCG and OCG Forbidden & Limited lists tracked here, Depth Amulet is Unlimited.
YGOPRODeck lists Depth Amulet for these formats: Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Depth Amulet appears in Ancient Prophecy (ANPR-EN070) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Depth Amulet is about $0.11 on TCGPlayer (prices change frequently).
