Felton’s, made in Canada Spira-Tuft brushes are heavily filled and rugged brushing tools which are easily adapted to hand or power tools. The spiral construction gives the SpiraTuft more flexibility than the Chucktuft brushes. This design feature is useful when brushing irregular or non-standard size holes, since the flexibility will permit the brush to readily conform to the existing shape. Features a single stem, single spiral. NOTE: The inside diameter of the flue is approximately 1/4" smaller than the outside diameter. The diameter of the flue brush will equal the inside diameter of the flue. High grade USA steel wire.