Rectangular Paint Grip Steel Downspouts are the standard for Paint Grip Steel K Style gutter systems. 2x3 is typical for a 5" K Style gutter system, however 3x4 can also be used and is considered a better alternative due to the larger amount of rainfall they can drain. 3x4 are typical for a 6" K Style gutter system and 4x5 for larger roof areas and commercial structures.
Bonderized "Paint Grip" Steel is galvanized steel that is processed through a phosphate bath. This provides a corrosion inhibiting, crystalline zinc phosphate, micro-porous surface that promotes adhesion of top coatings.