Extech sdl550 moisture content meter and datalogger extech sdl550 the extech sdl550 moisture content meter and datalogger records data on an sd card in microsoft excel reg format for easy transfer to a pc for analysis the user can manually store 99 readings or set the logger to automatically store up to 20m samples with date and time stamp at a user selected sample rate it measures moisture content air temperature dew point and temperature using a 600mm 23 7in heavy duty stainless stee