The Fire & Acoustic Door Drop Seals are designed for the gap between the door bottom and floor,it provides an excellent barrier to airborne sound and helping to ensure that the acoustic attenuation provided by a door set .

The Fire & Acoustic Door Drop Seals control the movement of the inner sealing strip through mechanical movement . When the door is closed , internal sealing strip will be down automatically to performance the tight sealing effects. When the door is opened, the inner seals will be automatically rise from the floor. Some of this serious seal can be fully hidden in the door bottom groove, the door beautiful surface will not be affected by installation of the seal. 

Loading: Heavy
Location: Single and double butt hinged doors bottoms. Min door thickness 50mm for rebated meeting stiles and 40mm for plain meeting stiles(for semi mortice)
Installation: Mounted into a 27mm x 44mm groove that has been morticed into the bottom edge of the door. Place the seal inside of the groove and fix the cover plates on both ends 
Min / Max Gap: 3mm to 13mm
Length :650-1500mm (Provide 100mm for cutting on the end)
Appearance: Grind arenaceous oxidation surface, Silver
Seal material：Silicon rubber or EPDM seal.