Dwyer 160F-KIT Stainless Steel Straight Pitot Tube Set contains the 160F-18, 160F-24, 160F-36, 160F-48 and carrying case. These pitot tubes are constructed out of a durable stainless steel with etched insertion depth graduations and a flow alignment indicator to keep the pitot tubes parallel with air flow. All of the pitot tubes easily fit into ducts through grills due to their straight design.