Made of 316 non-magnetic stainless steel. 7/32" - 1/4" glass slides easily on heavy plastic strip in bottom of each channel over felt cushion. Permits installation screws to be countersunk and tightened for proper clearance. Polypropylene pile fabric will not rot or mildew. The single flexible channel can be used straight or bent for rounded corners. Edge channel seals the opening between two windows of 3/16" or 1/4" thickness. For installation of edge channel use SealStrip glass setting tape on edge of pane. Use double channel for double windows. 8' lengths.