All-Clad TK™ 5-Ply Copper Core 3-qt sauce pan with D5 Lid. It"s a Perfect Match. the All-Clad TK collection is a unique collaboration with Thomas Keller, one of the world's most celebrated chefs. Designed to bring Chef Keller's cookware preferences to home cooks, these All-Clad-crafted pans reflect his philosophy that any cookware collection should include a mix of materials intended for specific tasks. This sauce pot features copper-core five-ply construction for quick heat-up time and precise temperature control attributes that make it ideal for simmering delicate sauces, reheating foods, and cooking soups, vegetables, beans and grains.