ALARM INDICATING W/PROTEC LENS 20A. Color-coded indicator flags indicate ampere rating. Body is constructed of black polyphenylene sulfide with UL-94V0 flammability rating, contacts are of bright alloy-plated beryllium copper. Ideal for telecommunications and control panel circuits.Eliminates down time by immediately pinpointing the blown (open) circuit while triggering LED or audio alarm, while placed in mating holder (482 Series). Clear plastic lens option available for additional safety.