Our Frameless Shower Door Tubular Back-to-Back Towel Bars with metal washers are constructed of thick brass tubing. The 3/16 inch low profile end caps make this bar an deal choice for most by-pass sliding doors. Decorative metal backup washers are included, as well as plastic washers to protectect against glass-to-metal contact. Available in nine sizes and eight popular finishes. Fits 1/4 to 1/2 inch thick glass. Requires two 1/2 inch diameter holes.