This pair of 1950s mid-century chrome bathroom sink leg supports is designed to support classic cast iron wall-mount lavatory sinks. The heavy-duty pair of Sears Homart brand lavatory legs pictured above were found in a basement complete and in excellent condition with their original box. Here's the copy from the original label on the box:
"Attractively designed for beauty as well as utility...For either vitreous china or cast iron lavatories...Streamlined, tapered legs of brass tubing with jewel-like polished chromium finish...Adjustable to length desired, 3 1/2-inch adjustment...Designed especially to go with Towel Bar No. 2083".
Wall-mount sinks that require leg supports can be identified by two small tabs hidden under the front corners of the sink. These tabs fit into the special rectangular metal brackets shown in the photo above, and the legs are turned to lengthen and tighten into place (similar to a shower curtain rod).