Hero Signal

Normal Trap

When a monster you control is destroyed by battle and sent to the Graveyard: Special Summon 1 Level 4 or lower "Elemental HERO" monster from your hand or Deck.

Rulings – Yugipedia

Printings:

The Lost Millennium: TLM-EN049 (Rare) - 2005-06-01
The Lost Millennium: TLM-EN049 (Ultimate Rare) - 2005-06-01
Duelist Pack: Jaden Yuki: DP1-EN028 (Common) - 2006-02-08
Dark Revelation Volume 3: DR3-EN229 (Rare) - 2006-11-25
Legendary Collection 2: The Duel Academy Years Mega Pack: LCGX-EN107 (Common) - 2011-10-04
Ra Yellow Mega Pack: RYMP-EN031 (Super Rare) - 2012-02-17
HERO Strike Structure Deck: SDHS-EN035 (Common) - 2015-01-29
Speed Duel GX: Duel Academy Box: SGX1-ENA20 (Common) - 2022-03-17
Legendary Duelists: Season 3: LDS3-EN115 (Common) - 2022-07-21
Speed Duel GX: Midterm Paradox: SGX2-ENA18 (Common) - 2022-10-06
Speed Duel GX: Duelists of Shadows: SGX3-ENA18 (Common) - 2023-03-30

Prices:

Cardmarket: 0.02 €
TCGplayer: $ 0.08