Tempered steel blade with aluminum mounting. Rubber handle. No. 15677: Model No. NT677, 3 16-Inch x 5 32-Inch , triangular notch No. 15669: Model No. NT669, 1 16-Inch x 1 16-Inch , square notch No. 15671: Model No. NT671, 1 4-Inch x 1 4-Inch , square notch.