Fusetron FRS-R-12 is a type of fuse made by the company Fusetron. It is a dual-element, time-delay fuse with a current rating of 12 amps and a voltage rating of 600 volts. It is commonly used in residential and commercial electrical systems to protect against overcurrent and short circuit faults. The “R” in the model number likely stands for “Residential” indicating that it is intended for use in residential applications.