Inductive Position Contactless Sensor, LVIT Technology, price and stroke to length ratio competes with potentiometers, ranges from 25mm to 200 mm, linearity <+/-0.15%, many analogue inputs and outputs, voltage or current, sealed to IP 67 with M12 connector or cable exit, 19mm diameter, click here for the data sheet: 

LR-19

Inductive Position Contactless Transducer for heavy duty industrial use, price and stroke to length ratio competes with linear potentiometers, ranges from 50mm to 200mm, linearity +/-0.15%, many analogue inputs and outputs, voltage or current, sealed to IP67 with M12 connector or cable exit, 27mm diameter, click here for the data sheet: 

LR-27