SnoBlox plastic snow guards are manufactured from virgin grade, UV-stable, polycarbonate. This is the same material used on the astronaut’s face masks. From the originators of polycarbonate snow guards, our products have helped prevent damage from snow and ice avalanches on sloped metal roofs since 1976. This kit is designed for either screw-down or standing seam metal roofs where roof penetrations are not desirable. Kit Includes 25 SnoBlox Deuce Snow Stops and 1 tube SureBond SB-190 EverSeal adhesive. Pull down from the menu to pick your color. Detailed instructions for installation are pictured in the listing. Placement of snow guards in isolated areas such as chimneys, doorways, vents, and partial roof sections is NOT recommended. A spacing recommendation and layout tool for snow guards is available online. Strong, Durable Design A flat, forward-facing design is proven to cause less roof stress, failures, and leaks than other competing options. Triple Strength Waffle Base Each snow guard holds 3,456 pounds when attached with screws and 1,379 pounds when attached with our recommended adhesive. This is nearly triple the strength of smooth bottom guards of the same size. SureBond SB-190 is the Industry Standard For Snow Guards Attach To Your Roof Without Penetrations. For a successful installation the adhesive requires 28 days or (672 Hours) at 50 Degrees (F) or above to achieve full cure. Simple Glue-Down Installation The mounting versatility of this product allows it to be adhesive mounted to screw down roofs with at least a 1.5" flat area or on floating standing seam roof systems.