Trevenant & Dusknoir-GX #SM217 from SM Black Star Promos is a reverse holo promo card that currently sells for about $17.00 ungraded, with graded copies ranging from $19.50 at grade 7 to $250 at grade 10. A grade 10 copy sells for around $250, about 15× the $17.00 raw price, so high-grade copies are worth grading.