Polypropylene handle injected directly on the tang. NSF Certificate: The Professional master line products are certified by the National Sanitation Foundation (NSF), an organisation acknowledged as the main international authority on food safety and hygiene practices. Quality and durability for hardworking professionals. With cutting edge technology, Tramontina professional knives are always ready to jump into action and do beautifully well with any ingredient, cut, or recipe. Efficiency all-around. The incredible high quality of the blades is a result of a thermal treatment which consists of hardening (heating the blade), subzero (cooling from 50 to -196 degrees), and tempering (increasing the steel elasticity) for a longer and more efficient life. The anatomical and ergonomic textured polypropylene handle, is directly injected on the steel bolster, ensuring a comfortable, safe use.