... Ambient temperature,-30 ~ +501.5 degreeRelative humidity, ≤95%1.6 Atmospheric pressure, 80~110Kpa 1.7 Defend grade, IP 672.Main features ... 16Ω)3.0 Installed ,wall-mounted 3 Specification3.1 This type of explosion-proof telephone made of si-aluminium alloy die ... with dial-up keyboard, high-performance glue sealing handle, hang pressure by induction fork of non-contact switch, Increased-safety connecting ...