BEP Pro-Installer Class-T Fuse Holder with 2 Studs 400-600A. Official RAM Mounts Motorcycle Yoke Fork Stem Base Mount with 1" Ball RAM-B-342U (#294446040064). Fuse mounting studs: 10mm (3/8") 225-400A holder, 12mm (1/2") 450-600A holder.
eBay