777 Axial Lead Fuse Littelfuse 777 Axial Lead Fuse, measuring 3.6mm x 9mm, is designed for overcurrent protection in electronic appliance charger applications. With an improved interrupting rating, the epoxy coated device opens safely on a direct short without producing soot, sparks, sounds, or explosions. Littelfuse 777 series can withstand up to 24 hits of 7.5kV ringwave surge. A higher surge withstand capability prevents nuisance tripping of fuse caused by transient surges. The compact size and enhanced electrical characteristics make this series ideal for use in safe and fast charging applications for smartphones and tablets.