FIG. 1 is a front perspective view of an embodiment of a tube rack comprising a new, original and ornamental design;
FIG. 2 is a rear perspective view of the tube rack shown in FIG. 1;
FIG. 3 is a front elevational view of the tube rack shown in FIG. 1;
FIG. 4 is a rear elevational view of the tube rack shown in FIG. 1;
FIG. 5 is a right side elevational view of the tube rack shown in FIG. 1;
FIG. 6 is a left side elevational view of the tube rack shown in FIG. 1;
FIG. 7 is a top plan view of the tube rack shown in FIG. 1;
FIG. 8 is a bottom plan view of the tube rack shown in FIG. 1;
FIG. 9 is a front perspective view of the tube rack shown in FIG. 1 in an alternate configuration;
FIG. 10 is a front elevational view of the tube rack shown in FIG. 9;
FIG. 11 is a front perspective view of the tube rack shown in FIG. 1 in an alternate configuration;
FIG. 12 is a front elevational view of the tube rack shown in FIG. 11;
FIG. 13 is a rear elevational view of the tube rack shown in FIG. 11;
FIG. 14 is a left side elevational view of the tube rack shown in FIG. 11;
FIG. 15 is a right side elevational view of the tube rack shown in FIG. 11;
FIG. 16 is a top plan view of the tube rack shown in FIG. 11;
FIG. 17 is a bottom plan view of the tube rack shown in FIG. 11;
FIG. 18 is a front perspective view of an embodiment of a tube rack comprising a new, original and ornamental design;
FIG. 19 is a right side elevational view of the tube rack shown in FIG. 18;
FIG. 20 is a left side elevational view of the tube rack shown in FIG. 18;
FIG. 21 is a right side elevational view of the tube rack shown in FIG. 18 in an alternate configuration; and,
FIG. 22 is a rear perspective view of the tube rack shown in FIG. 18.
The broken lines depict environmental subject matter only and form no part of the claimed design.