Holderbat Brass - 22mmA Holderbat Brass 22mm is typically a plumbing fitting used to secure and support 22mm copper or brass pipes in place. Made from brass, which is durable, corrosion resistant, and suitable for water systems. Designed for 22mm diameter pipes (a standard pipe size in plumbing). It "holds" the pipe securely against a wall, floor, or other surfaces, preventing movement, vibration, or stress on joints and fittings.