Maxi Auto Fuse Holders Keystone Electronics Maxi Auto Fuse Holders are designed to secure positioning during soldering. These fuse holders include low insertion force and reliable and compact automotive blade fuse holders for maxi-style auto blade fuses. The maxi auto fuse holders feature 40A and 50A current ratings and fully insulated clips to protect fuses and reduce assembly time. The insulators are PA9T black Nylon with Tin-Nickel plated Brass contacts to withstand shock and vibration. These fuse holders are available in Thru-Hole (THM) (Cat. No. 3581) and Surface Mount (SMT) (Cat. No 3582).