FEATURES 1).Sunlight measurement up to 1999w/m2 or 634BTU/(ft2*h) 2).High accuracy and rapid response 3).Data HOLD funtction to hold measurement values 4).Unit and sign display for easy reading 5).Measuring unit selection among w/m2 and BTU/(ft2*h) 6).Manual scale selection 7).Direct reading with no adjustments needed 8).Maximum and minimum values 9).Low battery indication Specification 1).operating temp&RH:5 —40 ,below 80%RH. 2).Storage temp &RH:-10 --60 ,below 70%. 3).