Your search for "Red Resonator SDSB-EN020" revealed the following:
Red Resonator - SDSB-EN020 - Common - 1st Edition from Structure Deck: Soulburner 1st Edition, available at 401 Games Canada. Rarity: Common Card Text:When this card is Normal Summoned: You can Special Summon 1 Level 4 or lower monster from...
Red Resonator - SDCK-EN007 - Common - 1st Edition from Structure Deck: The Crimson King 1st Edition, available at 401 Games Canada. Rarity: Common Card Text:When this card is Normal Summoned: You can Special Summon 1 Level 4 or lower...