The Rockwood 2949 Self Latching Flush Bolt With Bottom Fire Bolt For Fire Rated Wood Doors, 2949 Is Non-handed, Low (5 lbs. maximum) closing force. Self-latching top bolt, Override feature prevents damage to doors or bolts if the bolt head is blocked from entering the strike. Rockwood 2949 Thermal lock automatically locks the inactive door under high heat conditions due to fire, Bottom fire bolt eliminates the need for floor prep. See Manuf Specs.