Each bracket is made from lightweight billet aluminum and is precision fit to your carburetor for precise activation of the micro switch. Brackets will fit multiple applications including Holley 4150/4500 HP and 4150/4500 non-HP series carburetors. The bracket will work with a standard secondary arm as well as a throttle adjustment-screw secondary arm. Each bracket kit comes complete with stainless steel mounting hardware for the micro switch as well as for mounting the bracket. Bracket kits are available with or without a micro switch.