3549 Precision Potentiometer w/ Dual Ball Bearing Bourns 3549 10-Turn Precision Potentiometers now have a 'dual ball bearing' option specifically designed for machine-to-machine applications. The 'dual ball bearing' feature of the 3549 series potentiometers from Bourns, available only in the Hybritron® servo-mount version, is capable of 10 million shaft revolutions with up to 250 grams of side load. Features of the 3549 series include wirewound and Hybritron® elements, high rotational life, standard resistance range 100Ω to 100KΩ (wirewound) and 1KΩ to 100KΩ (Hybritron®), optional 0.1% linearity, and operating temperature range up to +125°C.