Kool Black Box 100s are menthol cigarettes from the Kool brand, sold at Costco in a carton format. Kool is one of the most recognized menthol cigarette brands in the United States, manufactured by ITG Brands (formerly Brown & Williamson). The Black variety features a smooth menthol flavor profile in the 100mm king-size format, presented in a hard box packaging. The "6M CS" in the original description indicates a case pack of 6 cartons, each carton containing standard packs of cigarettes.