The feeder for the controlled transfer of product items into the pockets of a web of sheeting has a base unit, a supply container for holding the product items, and a product conveyor for receiving the product items from the supply container. Further, the feeder has an exchangeable format unit including a sorting plate for receiving the product items from the product conveyor, a filling unit with a number of vertically extending filling tubes for receiving the product items from the sorting plate and with a blocking slide unit with a blocking slide plate for temporarily blocking the guiding channels of the filling tubes. The format unit further has a filling shoe for receiving the product items from the filling unit and for guiding them to the pockets of the web of sheeting. A plurality of drives and the corresponding electrical control components for moving the format unit, the sorting plate, the blocking slide plate and the filling shoe are arranged in the base unit.