The metal-detectable Penguin safety knife is a robust, versatile cutter featuring twin cutting The metal-detectable Penguin 400M is a light-use safety knife that is excellent for cutting netting, plastic packaging, shrink-wrap, string and paper. The Penguin 400M is ideal for use in food manufacturing and clean rooms. The stainless steel blade is completely protected, molded into the plastic and sealed to keep out bacteria. Available in blue only.