Your search for "Power Injector CSOC-EN021" revealed the following:
Power Injector - CSOC-EN021 - Common - Unlimited from Crossroads of Chaos Unlimited, available at 401 Games Canada. Rarity: Common Card Text:Once per turn you can pay 600 Life Points to have all face-up Psychic-Type monsters gain 500 ATK during...
Power Injector - CSOC-EN021 - Common - 1st Edition from Crossroads of Chaos 1st Edition, available at 401 Games Canada. Rarity: Common Card Text:Once per turn you can pay 600 Life Points to have all face-up Psychic-Type monsters gain 500...