Marathon/Kulka CJ660 fuse holder covers are designed to provide consistent protection in accordance with IEC Standard 529, designation IP20 (finger safe). These covers are constructed from thermoplastic material with a thermal rating of 125°C and are UL listed. They allow for visual inspection of self-indicating fuses and provide access for test probes and re-tightening of wire terminations. The covers are compatible with a wide range of fuse holder brands, making them a versatile solution for various industrial applications.