Nailor 0757, 0757D, and 0763 Ceiling Dampers for use in Wood Truss ceilings are component dampers for use with field fabricated plenums (by others).
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Models 0757/0757D are listed for UL designs L528/L546/L550/L558/L562/L574/L576/L579/L581/L583/L585/M501/M503 and roof/ceiling design numbers P531/P533/P538/P545/P547/P552.
Model 0763 is listed for UL designs L528/L546/L550/L558/L574/L576/L579/L581/L583/L585/M503 and roof/ceiling design numbers P531/P533/P545/P547/P552.