If your opponent controls a monster and you control no monsters, you can Special Summon this card (from your hand). You can only use this effect of "Unknown Synchron" once per Duel.
NM-Mint 1st Edition - $0.25
Lightly Played 1st Edition - $0.23
Moderately Played 1st Edition - $0.20
Heavily Played 1st Edition - $0.17
Damaged 1st Edition - $0.13
NM-Mint 1st Edition Non English - $0.25
Lightly Played 1st Edition Non English - $0.23
Moderately Played 1st Edition Non English - $0.20
Heavily Played 1st Edition Non English - $0.17
Damaged 1st Edition Non English - $0.13