Accumulation conveyors hold product on the conveyor until given a signal to release the product. Typical applications include feeding product to a machine such as a case sealer at a specified rate, or holding items to be shipped until a truck is ready to be loaded. Accumulation conveyors are similar to power roller conveyors in function, with some exceptions. The drive pressure on the product can be adjusted to a minimum, or eliminated altogether. This is useful when a long line of cartons have to be accumulated without pressure so they can be utilized in a process such as loading, sorting, taping, strapping, palletizing, or picking. In minimum pressure accumulation, conveyed products lightly touch each other. The driving of the tread rollers on minimum pressure conveyor is accomplished with the top surface of a standard section flat belt. In zero-pressure accumulation, conveyed products rarely touch each other and place no force on product when it stops.