Powder-actuated tools (PAT) use an explosive gunpowder charge to provide high force for driving pins into concrete, steel, and hard backing materials. Powder charges are fed one at a time to the tool. They are color-coded and numbered to indicate the power of the charge to help ensure users use the correct charge for the fasteners. Pins have round heads similar to nails. They come on strips and are fed into the tool one at a time. OSHA regulations require training and certification for employees who use powder-actuated tools and charges.