Waterfowl Duplex Shotgun Loads, often referred to as duplex loads, are a type of shotgun shell designed to facilitate effective waterfowl hunting. They consist of two or more different sizes of shot layered or mixed together within the same shell. This combination allows the shooter to benefit from the characteristics of both shot sizes simultaneously. Typically, the larger shot is used to maintain lethal energy at longer ranges, while the smaller shot provides a denser pattern for close-range shooting.