Product Details:

Easy to Install
Eliminates Drafts
Theft-Proof Locking Device

CRL No-Draft Speak-Thrus are designed to allow audible transmission of voice requests at ticket windows, box offices and more. They prevent tampering from the outside, and stop drafts to the interior. The CRL 549 Series is made of brass. Each unit is individually boxed with gaskets and mounting screws for installation on glass up to 1/4 inch (6.4 millimeter) thick.
For thicker glass up to 3-3/4 inch (95 millimeters), you can use the optional four inch (102 millimeter) screws Cat. No. 8324.
CRL No-Draft Speak-Thrus require a minimum hole diameter of 2-1/4 inch (57 millimeters), and will cover holes up to 4-1/4 inch (108 millimeters).
Recommended hole diameter is 3-1/2 inches (89 millimeters).

Color:                            Satin Anodized
Minimum Hole Diameter: 2-1/4 in (57 mm)
Maximum Hole Diameter: 4-1/4 in (108 mm)

Minimum Order: 1 Each