Material：
Galvanized steel Plate (G)
Stainless steel plate (S)

Characteristics：
Fire-resistant fuse 74°c, 280°c.
The blade and the frame surface are fastened with the spring by the bumper.
Imported insurance chip Melt degree 74°c or 280°c, insurance chip fuse damper blade is closed.
Insurance pieces of the United States UL inspection, fire time 1.5 hours.
The throttle is too large to adopt segmented compartments, reinforcing.
The blade and the frame surface rotate the axle to have the stainless steel continuous motion piece to windproof leaks.

Square Type Damper

Round throttle 2

Round throttle 3