Stim-Pack 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, Stim-Pack is Unlimited.
YGOPRODeck lists Stim-Pack for these formats: GOAT, OCG GOAT, Duel Links, Common Charity, Edison, TCG, OCG, Master Duel.
A listed print of Stim-Pack appears in Metal Raiders (MRD-141) at Short Print rarity.
Among markets shown on this page, the lowest listed snapshot for Stim-Pack is about $0.02 on Cardmarket (prices change frequently).
