The M28748/13G10L1A is a 3.9" diameter, 13 gauge steel tube produced by Winchester. The tube has an external galvanised finish, a bright interior zinc chromate finish, and a closed end. It is designed for use in heating, ventilation, and air conditioning (HVAC) systems, and is able to withstand a maximum pressure of 10 psi. The M28748/13G10L1A is also flame, corrosion, moisture and dust resistant.