Scrapers are injection molded from chemically- resistant polypropylene. Blades are made from heat-treated high-carbon steel and secured to handle with machine screw and nut assembly. 2 models feature a work knob for extra pressure on tough jobs. Use replacement blade model No. 8391 (SKU 775037) for 1-3/4" scraper or model No. 8389 (SKU 775045) for 2-1/2" scraper.