Mantine δ, from the Dragon Frontiers set, is a Rare rarity Reverse Holofoil card, numbered 20 in the series. Currently valued at $27.78, it appeals to collectors due to its unique Delta Species designation and striking holographic finish. The card's market presence is bolstered by its limited availability, making it a notable addition to any Pokémon trading card collection. Grading and sales trends indicate steady interest among enthusiasts.