We claim the ornamental design for a compressor unit, as shown and described.
FIG. 1 is a front perspective view of a compressor unit having a foot.
FIG. 2 is a left side view of the compressor unit shown in FIG. 1.
FIG. 3 is a rear view of the compressor unit shown in FIG. 1; and,
FIG. 4 is a bottom view of the compressor unit shown in FIG. 1.
Broken lines having equal length segments illustrate unclaimed portions of the compressor unit and form no part of the claimed design. Broken lines having unequal length segments illustrate the boundary of the claimed design and form no part of the claimed design.