GutterBrush ™ is a simple "Twisted in Wire" brush, similar to a large, heavy-duty bottle brush. It is constructed from a galvanized steel core and double UV protected, durable polypropylene bristles. Simple to install and maintain: no tools required. Affordable solution vs. most alternatives. Versatile - can be used with almost any roof or gutter type. Effective barrier to leaves and debris: 360-degree internal protection blocks leaves, branches, nesting birds, rodents and insects. When installed, stiff GutterBrush bristles fill the gutter, blocking leaves and debris from entering. The entire gutter remains open, allowing water to flow freely through the brush and drain path. Available in: 4" Small for Mobile Homes, Sun Room, Lanais, etc.; 5" Standard for K-Style, OG, Half Round and Fascia Gutters; 6" Oversized for Residential and Commercial Gutters; 7" Super for Larger Gutter Systems and 8" Industrial, for Industrial Gutter Systems. To determine which size you need, measure your gutter opening from the back of the gutter to the front lip.