FIG. 1 is a right front perspective of a combined waterbed filling and draining tube, showing my new design;

FIG. 2 is an elevational view of one side, thereof;

FIG. 3 is a front elevational view, thereof;

FIG. 4 is an elevational view of the other side, thereof;

FIG. 5 is a rear elevational view, thereof;

FIG. 6 is a bottom plan view, thereof;

FIG. 7 is a top plan view, thereof; and,

FIG. 8 is a rear elevational view, thereof, taken to a reduced scale, the broken line representation of the upper and lower edges of a waterbed mattress being shown solely for illustrative purposes, forming no part of the claimed design.