The Entei EX (103 / 108) card can be found in the Dark Explorers set.
Recently sold 2 times and based on those sales is worth around £41.24.
Currently, there is 1 open listing for this card on ebay.
This card sells in the range of £39.95 to £42.53, making it very stable.
This Rare Ultra card was illustrated by 5ban Graphics.
The fact that it is a EX card makes it one of the more valuable cards.