The Chapin Ground-Driven Tow-Behind Trailer Sprayer uses the patent-pending Tube Compression Peristaltic Pump to ensure that the flow rate varies with the speed of the tractor or ATV towing it. The peristaltic pump system has three turning rollers, which flatten the flexible hose to force liquid through a nozzle. There is no need to pressurize or pump air into the tank. This unique system provides pressure as the rollers compress the tube and move the contents. This totally mechanical system does not require a battery hook up. Flow rate varies with speed so that you never over- or under-apply fertilizers or herbicides.