... .3,the working ter\mperature of this unit is 15-30 degree and it must be powered off after continuously working ... by DHL,FEDEX,UPS,EMS,TNT, you can choose anyone as you like, because we are a big manufacturer,large quantity ... semiconductor laser light properties, demanding job ambient temperature is 15-30 degrees, work continuously 2 hours, should be shut off after 10 ...