This plate belongs to a **waste compactor (garbage truck)** of the type **"The Leach Packmaster"**. The "Leach Company" is one of the most famous historical companies known in America for manufacturing waste truck bodies and mounting them on various truck chassis. According to the model written (S11-16-YD), the number **16** usually refers to the rear container capacity, estimated at **16 cubic yards** (YD).