The shredding industry offers its services to customers in a few different ways. Off-site shredding is widely used by recycling plants for tires, wood, organic materials, old automobiles, scrap metals, plastics and cardboard. In this method, the materials are transported to a shredding facility where they are destroyed. Some document shredding companies pick up the materials to be shredded and transport them to the facility where they are shredded in the same day. Other companies offer mobile shredding; this service brings large shredders on a truck to different businesses for the on-site shredding of documents. The trucks are often modified box trucks with industrial shredders inside. Colleges, law firms, hospitals and other entities that produce a high volume of sensitive documents make use of mobile shredding services, often in order to comply with federal privacy protection regulations. The Health Insurance Portability and Accountability Act, for example, requires that hospitals dispose of sensitive documents in a certain way. Mobile shredding services can be a way to independently certify the proper destruction of documents.Industrial shredders all feature a feed area with blades or gears for crushing or slicing material, and a chute that passes the material into a receptacle or conveyor for further handling. Many are equipped with screens that control the particle size of the finished product. The larger material that can't pass through the screens is then sent through the shredder as many more times as is necessary. Wood products and materials such as branches, cardboard boxes, crates and particle board are often shredded for recycling or conversion into other products. Chipper shredders cut wood into chip form, which reduces their bulk for easier disposal. Wood chips are also often used outdoors on walkways, in playgrounds and in landscaping or gardening. Used cardboard boxes and cartons are often shredded by steel cutters or shears to produce packing material. Other wood waste such as pallets, crates or blocks are shredded and manufactured into briquette presses or prepared for heating furnaces. Shredders may be hand fed by workers, which is rarely still done because of safety concerns, put on a conveyor and fed into the shredder by meter feeding, or loaded by a forklift via batch feeding.