The device

1. An alphanumeric display of 16 characters by two lines offers enough space to present results and adjust parameters.
2. A serial number uniquely identifies each device.
3. The supplied battery charger is attached to this connector.
4. Three waterproof buttons allow to start measurements, adjust parameters and to power on/off the device. They can be pressed with the thumb of the same hand that holds the instrument and are sealed against water and dirt to the IP67 standard.
5. The grip has a diameter of 55mm (2.2 inches), which allows to comfortably hold the instrument in one hand.
6. Two rechargeable AA-type batteries are located behind this lid. With a life-span of at least 500 charge-cycles they seldom need to be replaced.
7. The photometric sensor is located at the tip of the probe. It is directly immersed into the raw sample and uses three different wavelengths to perform the measurement.