... Temperature40o to 140o F/-40o to 60o CHumidity5% to 95% ( Non-condensing)Seismic PerformanceRepeatedly dropped from 1.5 m high concrete ... CLASSAProcesswith filter devicesNo Weld false welding phenomenonLenses clean, no bubbles, non-destructive crackScrew firmly, without looseningAdjustable stabilityNo loss on the plastic device ...