Oracle Text

Artifact

{X}, {T}: You may exile a nonland card from your hand. You may cast that card for as long as it remains exiled. Put a charge counter on this artifact and note the type and amount of mana spent to pay this activation cost. Activate only if there are no charge counters on this artifact. {T}, Remove a charge counter from this artifact: Add this artifact's last noted type and amount of mana. Spend this mana only to cast the last card exiled with this artifact.