FIG. 1 is a perspective view of a base unit taken from above, front and one side;

FIG. 2 is a persective view thereof, taken from below and the side illustrated in FIG. 1;

FIG. 3 is a top plan view thereof;

FIG. 4 is a side elevational view thereof, taken from the side illustrated in FIG. 1;

FIG. 5 is a side elevational view thereof, taken from the side opposite that illustrated in FIG. 1;

FIG. 6 is front elevational view thereof; and,

FIG. 7 is a rear elevational view thereof.