Electromagnetic Shield is a Continuous 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, Electromagnetic Shield is Unlimited.
YGOPRODeck lists Electromagnetic Shield for these formats: TCG, OCG, Master Duel.
A listed print of Electromagnetic Shield appears in The Shining Darkness (TSHD-EN055) at Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Electromagnetic Shield is about $0.17 on Cardmarket (prices change frequently).
