It was invented by Crofton Nelle M and filed on January 8, 1944. It was issued on August 10, 1948 by the United States Patent and Trademark Office. ProductSiteLaunchDate : 2018-06-04T14:08:43.975Z Size : 16" x 20" Style : Classic SupplierDeclaredDgHzRegulation1 : not_applicable SupplierDeclaredDgHzRegulation2 : not_applicable SupplierDeclaredDgHzRegulation3 : not_applicable SupplierDeclaredDgHzRegulation4 : not_applicable SupplierDeclaredDgHzRegulation5 : not_applicable SurfaceRecommendation : Concrete UnitCount : 1 UnspscCode : 47131600