QO and QOB one, two and three pole thermal magnetic circuit breakers provide overcurrent protection and switching on ac and dc systems. These circuit breakers have an over center, trip-free toggle mechanism with quick-make, quick break action and positive handle indication A full line of factory installed accessories, such as shunt trips, auxiliary switches and alarm switches, is also available QOU Accessories for QO™ and QOU Miniature Circuit Breakers, QO1PL, is a Handle Padlock Attachment for Padlocking in ON or OFF position with fixed attacheMount. This accessory is a I-line hanger that is rated at 400 A and is installed horiziontal and used seismic applications. This accessory is UL and CSA certified product.