1" x 3" Rectangular Tubing Plugs RER-1X3-14-20 (4) Plugs Plugs for Rectangular Tubing Plugs for rectangular tubing feature a series of externally tapered ribs designed to provide a sure grip inside a tube without the unsightly plastic shavings. Durable construction for use with rectangle-shaped tubing Exceptional performance in business and commercial applications Material: Low-density polyethylene Service Temperature: -94 - 175° F (-70 - 79° C) Standard Color: Black