Sandstorm also helps shut down any opposing Pokemon that might try and change the weather—once they have been sufficiently weakened,a Choice Band Pursuit can often cripple them enough to prevent them from switching in again.
Eviolite boosts theDefense and Special Defense of NFE Pokemon by 50% each, and withDusclops's already impressive defenses, makes it exceptionally hard to take down. Those impressivedefenses let it switch in on Excadrill, one of the best Rapid Spinners in the game, survive two Earthquakes, and then use Pain Split to heal its health.
Choice Scarf is an option with a Jolly nature as it allows Zweilous to outspeed Pokemon with 110 base Speed and max Speed EVs, but is generally better left to a Pokemon with better movepool options such as Honchkrow.
^ now that choice scarf is a set, the OO mention should be removed