Oil Mist Hydrocarbon, Gas Detector Tubes for Compressed Breathing Air,OC-F08 Fixed Nitrogen(N2) gas detector with data logger function – Oceanus gas detection system include of the Fixed gas detector, Portable gas detector, Air quality monitor system,Fixed Nitrogen (N2) Gas Detector, 0 to 100% Vol,NITROGEN くわしく GAS ペリスコープ(潜望鏡)