The term "Seamless Gutter" is a general term for the most common style gutter on the market; similar to the profile picture above (notice the reverse curve on the front.) Seamless Gutters AKA K-Style Gutters most often will be either 5" Standard or 6" Oversize. Seamless gutters are available in 4" small, 7" or 8", but 4", 7", and 8" are extremely rare. While we do have products for all sizes, below are the products most commonly recommended. GutterBrush is the simplest leaf guard for seamless gutters and it installs with no tools or fasteners! Just slide it in.