The Model 22 HDD Hard Drive Destruction System from Security Engineered Machinery of Westboro, Massachusetts, prevents data theft by shredding used computer hard drives into unreconstructible fragments. The unit can destroy twenty 31/2-inch hard disks each hour. It can also destroy other items, including hand-held electronic devices, computer backup tapes, and circuit boards. Custom units are available for destroying books, bound documents, plastic bottles, and defective or obsolete products. The built-in conveyor automatically adjusts the feeding speed to prevent jamming. A rotary knife mill in the destruction chamber cuts the waste until the particles are small enough to pass through a steel sizing screen, and the user can determine the particle size by choosing the mesh of the screen. Components are stainless steel so drive magnets will not adhere.