... ,Meaning Of The Button"A" means with total power switch, "no letters" said without total power switch:"B" means total stop ... + 40 degrees, 24 hours of their average not more than + 35 degreesb, the altitude: no more than 2000 Mc, atmospheric conditions: at the ... highest temperature for + 40 degrees, air relative humidity of no more than 50%, and under the low temperature can allow a ...