Alpha-class ARC Trooper
this was the name given to the first 100 clone troopers that were produced from the pure Jango Fett genome by the Kaminoans, during the early development of clones for Jedi Master Sifo-Dyas. The Alpha-class troopers were developed from the lessons learned in the development of the so-called Null-class ARC troopers, whose existence was a carefully-guarded secret.