US D312132 S
FIG. 1 is a perspective view of the surgical drainage unit, showing my new design, the broken line is for illustrative purposes only and forms no part of the claimed design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a left side elevational view thereof, the right side elevational view being identical thereto;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a bottom plan view thereof; and
FIG. 6 is a top plan view thereof.