Electro-Whip 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, Electro-Whip is Unlimited.
YGOPRODeck lists Electro-Whip for these formats: GOAT, OCG GOAT, Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Electro-Whip appears in Legend of Blue Eyes White Dragon (LOB-093) at Common rarity.
Among markets shown on this page, the lowest listed snapshot for Electro-Whip is about $0.04 on Cardmarket (prices change frequently).
