Company: Plazbox Mfg. Inc. Product: Plazbox Description: This all-in-one HVAC sheet metal box serves as a replacement for more than 100 metal ductwork parts and adaptors. It can replace 42 sheet metal ...

For my example I’m going to use an 8- x 8- x 8-inch sheet metal fitting called a ceiling register box, or C box, ... In other words, an 8- x 8-inch diffuser will fit an 8- x 8- x 8-inch C box. The ...