The OHMITE RJS35R is a wirewound rheostat, a type of variable resistor used for controlling electrical power. These rheostats are designed for durability and precision in industrial settings, offering adjustable resistance for a wide range of applications. They are subject to mechanical wear and have a finite life. Models H, J, G, K, L and N are listed under UL File No. E-10946 and CSA File No. 21309.