Small editorial note: I really do wish they'd just put 4 of each type in the main box. That really would've served basically all the need for them.
From the release:
Let nothing distract you from taking your shot. Speed up your games of X-Wing™ with the X-Wing™: Dice Pack, now available at your local retailer!
X-Wing pits two players against each other in a fast-paced battle for the fate of the galaxy. Rebel X-wings collide with Imperial TIEs in dramatic dogfights. Players maneuver their starfighters and try to blast their opponent’s ships to pieces. Combats are deadly and streamlined by the use of custom dice that keep players immersed in the action.