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1/2" Thickness 1-1/2" Wide x 50 Ft. Gray Smooth Wool Fiber Felt F13 Strip with Plain Backing: Amazon.com: Industrial & Scientific
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USA Sealing BULK-FS-F13-21 Grade F13 Felt Sheet, No Adhesive, 3/16" Height, 12" Width, 36" Length: Amazon.com: Industrial & Scientific
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