Dayton 3G-OTH-74740 — Technical Specifications

Name: Dayton 3G-OTH-74740 21"H-W 4.5"L Aluminum Backdraft Damper: For 18 in Fan, Single Panel, 21 in H, 21 in W, 2 in D, Felt (MPN 4HX66). Key specifications — Airflow Direction: Vertical; Blade Type: Flat Blade; Brand: DAYTON; Maximum Air Velocity: 2000 fpm; Mounting Position: Horizontal.
Brand: Dayton

The Dayton 4HX66 is a ceiling/roof-mount backdraft damper with a 21-inch height, 21-inch width, and 4.5-inch length, designed for use with an 18-inch fan. It features a single-panel flat blade design, felt seals, and a 2-inch depth, with vertical airflow direction and horizontal mounting position. The damper supports a maximum air velocity of 2000 fpm.

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Technical Specifications

Parameter	Value
D	2 in
H	21 in
Type	Single Panel, 21 in W, Felt
Brand	DAYTON
Blade Type	Flat Blade
Airflow Direction	Vertical
Mounting Position	Horizontal
Maximum Air Velocity	2000 fpm
Manufacturer Part Number	4HX66