FireRed & LeafGreen is a set in the EX series. It was released on September 1, 2004. The printed size is 112. This checklist is longer, at 116 cards. Multi Energy is 103/112, in position 103 of 116 on this checklist. Before it is 102 Switch, and after it is 104 Blastoise ex. The listed rarity is Rare.
Multi Energy is an Energy card. It is listed as Special.
Takumi Akabane illustrated this card. The same name is on 51 other cards in the catalog.
The card text says: Attach Multi Energy to 1 of your Pokémon. While in play, Multi Energy provides every type of Energy but provides only 1 Energy at a time. (Doesn't count as a basic Energy card when not in play.) Multi Energy provides Colorless Energy when attached to a Pokémon that already has Special Energy cards attached to it.
I keep a set binder for FireRed & LeafGreen, meant to hold every card of that set. This card is one slot in the FireRed & LeafGreen set binder. I still need this card.