A proofing air jet having a hollow elongated body having an air outlet and a suction inlet, the air outlet opposing the suction inlet, a pressurized air inlet into the body between the air outlet and the suction inlet, the pressurized air inlet being angled with respect to the hollow elongated body to flow pressurized air in a direction from the pressurized air inlet to the air outlet and provide a suction at the suction inlet, the air outlet having an innerduct/microduct connector for connecting to an opening of the innerduct/microduct, and the suction inlet having a string inlet configured to accept string, and the method further comprising blowing air through the pressurized air inlet into the hollow elongated body and into the innerduct/microduct, wherein the air sucks the string through the string inlet and carries the string through the hollow elongated body and through the innerduct/microduct. A plurality of the proofing air jets can be connected to a manifold. A method of proofing an innerduct/microduct using the proofing air jet to blow a string through the innerduct/microduct.