AUTOMATIC TRAP VENT Vents trap line Eliminates need for extension vent line Does not eliminate need for main vent stack Carded 5066340 AUTO VENT SIZE:1-1/2"
From the Manufacturer
LDR 506 6340 1 1/2-Inch Automatic Trap Vent, 1-1/2-Inch . 1-1/2-Inch Automatic Trap Vent eliminates the need for an extension vent line. Does not eliminate the need for the main vent stack.