Area/Volume Measuring key. Pythagorean proposition indirect measurement key. 30 Units Storage. Unit Conversion/Backlight. Water Bubble Level Indicator. Measuring Units : mm/in/ft. Continous Measurement Function. Area Measurement Function. Volume Measurement Function. Full Mode Pythagorean Proposition Measurement Function. Add/Subtract Measurement Function. Min/Max Value . Automatic Backlight . Button and Key Sound . Laser Level Class II.