Blue Mana Battery

Artifact, 4 (4)
{2}, {T}: Put a charge counter on Blue Mana Battery.

{T}, Remove any number of charge counters from Blue Mana Battery: Add {U} to your mana pool, then add an additional {U} to your mana pool for each charge counter removed this way.¹
Illus. Amy Weber

Gatherer Card Rulings [Nov 2009]

• 10/4/2004: Can be tapped even if it has no counters.

Format Legality	Legal in Vintage, Legacy Banned in Extended, Standard, MTGO Classic
Printings (2/12)	Fourth Edition (Rare) Legends (Uncommon (R1))