The Rockwood 2848 automatic flush bolt comes with a bottom fire bolt for metal fire-rated doors and comes non-handed. Rockwood Commercial Automatic Flush Bolt With Fire Bolt Requires a 5 lbs low closing force and has an override feature that prevents damage to doors or bolts if bolt heads are blocked from entering strikes. The Rockwood 2848 has a Thermal lock that automatically locks the inactive door under high heat conditions due to fire. Rockwood 2848 bottom fire bolt eliminates the need for floor prep.