Extech ph orp temperature data logger extech sdl100 the extech sdl100 ph orp temperature data logger 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 user defined intervals of up to 9 hours supplied with 6 x aa batteries 2gbyte sd card hard carrying case sample buffers mini ph electrode and thermistor temperat