The OHMITE RUS50RE is a wirewound rheostat, a type of variable resistor used for precise control in industrial applications. These rheostats are electro-mechanical devices, subject to mechanical wear and have a finite life. They are available in various configurations, including enclosed and open designs, with different shaft rotation options and torque ratings. Models H, J, G, K, L and RUS are listed under UL File No. E-10946 and CSA File No. 21309. All rheostats have a 10% tolerance.