NOS 90 degree bend nitrous bottle blowdown tubes are made from 1/2" 6061-T6 aluminum and available in blue or black anodized finishes. This type of tube is necessary when mounting a nitrous bottle inside the passenger compartment of a vehicle. It directs the nitrous outside of the vehicle in the case of an over-pressurization event. The 90 degree bend may be necessary for some nitrous bottle installations. Racer Safety Black Aluminum 90 Degree Blowdown Tube