Microchips MCP4018 series are a range of great digital potentiometers. This range includes volatile memory all in a mini SC70 (SOT-323) package. The MCP4018's include options to have it in a potentiometer or rheostat configuration and feature a wide range of voltage options, from 1.8V up to 5.5V. These potentiometers are7-bit resolution (128 wiper steps).
Digital potentiometers can be used in many applications that need a variable voltage resistance. Digital penetrometers are typically used where mechanical potentiometers are employed.