This hall effect linear magnetic sensor senses a magnetic field and produces a voltage proportionnal to the field, centered at Vcc/2.
This sensor enables to replace potentiometres for analog commands, avoiding any mechanical wear.
If you have a board that is already programmed for potentiometers, you can replace them with this type of sensor without reprogramming the board (but pay attention to the wiring which is different).
Sensitivity : 1.4 mV/Gauss
Supply voltage : from 2.7 to 6.5 Vdc
Data Sheet : http://www.electroseed.fr/docs/SS49E-hall-sensor.pdf