FKS ATO® Style Blade Fuses Littelfuse FKS ATO® Style Blade Fuses are rated at 80V and feature a three-part construction with copper contacts. They are also filled with arc-quenching material. These fuses offer excellent reliability in harsh environments as well as low voltage drop. Littelfuse FKS ATO Style Blade Fuses are offered in current ratings from 3A to 30A.