# Valid Sensor Ranges

Waterwatch sensors have limitations in the measurement distance.  If the sensor is too close or too far from the surface, the sensor is not able to record a valid measurement. Different types of sensors usually have their own minimum and maximum ranges.

| **Sensor model**              | **Min distance from surface** | **Max distance from surface** |
| ----------------------------- | ----------------------------- | ----------------------------- |
| *LS1*                         | 0.3 metre                     | 5 metres                      |
| <p><em>LS1-10M</em><br></p>   | 0.5 metre                     | 10 metres                     |
| <p><em>LS1-P</em><br></p>     | 0.1 metre                     | 10 metres                     |
| <p><em>LS1-P-20M</em><br></p> | 0.1 metre                     | 20 metres                     |
| <p><em>LS1-R</em><br></p>     | 0.2 metre                     | 7 metres                      |
| <p><em>T35</em><br></p>       | 0.2 metre                     | 3.5 metres                    |

Please note that the distance is calculated from the sensor module (not the device) to the surface. For example, for ***T35*** sensors, the sensor module is at the bottom of the sensor; for ***LS1-P*** sensors, the sensor module is the cylindar metal piece, attaching to the end of the cable.