MICO Brake Locks are supplemental safety devices that provide additional brake holding when used in conjunction with a vehicle's properly functioning mechanical parking brake*. There are several retrofits available for single, dual, split or anti-lock brake systems. MICO Brake Locks are ideal for construction, mining, agriculture, material handling, multi-stop delivery and recreational vehicles. They fit most medium and light duty trucks equipped with a hydraulic braking system. *MICO Brake Locks use the vehicle's service brakes as an operational supplement to the vehicle's properly functioning mechanical parking brake and are not intended for prolonged use.