The SDL150 records data on an SD card in Excel format. Dual backlit display of Oxygen Concentration and Temperature. Measures dissolved oxygen from 0 to 20.0mg/L and 0 to 100.0% oxygen plus temperature from 32 to 122°F (0 to 50°C). Automatic Temperature Compensation from 0 to 50°C via temperature probe sensor built into polarographic type oxygen probe. Offset adjustment used for zero function to make relative measurements. Stores 99 readings manually and 20M readings via 2G SD card. User programmable sampling rate. Built-in PC interface. Min/Max and Data Hold functions, Auto power off. Complete with 6 x AA batteries, SD card, probe, two spare replacement membranes, electrolyte, and hard carrying case.