It is called a coil set or a clapper solenoid. Check ebay or paintball-parts.com. You can also try google or the miscellaneous paintball equipment section of the BST. I don't guarantee a Spyder one, or any other one, will fit, but it is worth looking into.
** If your parents can't pay for your paintball stuff because they are too old and their social security checks are used to fund their retirement, put this in your signature**