Cyber Shield 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, Cyber Shield is Unlimited.
YGOPRODeck lists Cyber Shield for these formats: Speed Duel, OCG GOAT, Duel Links, Common Charity, TCG, OCG, Master Duel.
Cyber Shield belongs to the Harpie archetype—use that tag when searching for engine pieces and tech options.
A listed print of Cyber Shield appears in Legendary Collection 4: Joey's World Mega Pack (LCJW-EN105) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Cyber Shield is about $0.06 on Cardmarket (prices change frequently).
