Class1 Interlube filled pressure gauges with a patented Sub-Z II freeze-proof isolator are a must for all fire apparatus. Because the stem and bourdon tube are filled and sealed with a low temperature liquid, water cannot enter the tube. This prevents freezing and subsequent damage to the gauge.
The fill fluid in the case dampens pulsations and vibration while eliminating the need for snubber valves. In addition, Interlube fill eliminates fogged lenses, rust and corrosion.
The demands of fire fighting professionals for accurate and reliable instrument readings have been met by thousands of Class1 freeze proof pressure gauges that are now in service and meet or exceed NFPA and ANSI standards.