Advanced format ruling
Power Supplier
Card effect (current official text)Once per turn, you can select 1 face-up monster you control. It gains 400 ATK while you control this face-up card. (A monster cannot gain more than 400 ATK from this card's effect.)
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.