A compressor design includes a male rotor (10) having one or more helical lobes (12) and a female rotor (14) having one or more helical grooves (16). The male rotor is mounted on a first shaft and the female rotor is mounted on a second shaft. The male rotor is positioned in a first section of a chamber and the female rotor is positioned in a second section of the chamber. Fluid enters the chamber at an inlet, and when the rotors are driven, the lobes of the male rotor fit into the grooves of the female rotor, causing compression and movement of the fluid towards an outlet or discharge end where the compressed fluid is discharged. The configuration of the lobe and groove helix, the lobe and groove profile, and the outer diameter of the rotors can be varied in different combinations to form different rotors.