A self-tapping screw with a narrow shaft and rough threads is known as a chipboard screw or particleboard screw. Chipboard screws are designed to grip this composite substance and avoid pulling out because chipboard is composed of resin and wood dust or wood chips. The screws securely attach chipboard to other types of material, such as solid wood, or chipboard to other types of chipboard. Chipboard screws were developed to hold low, medium, and high density chip boards together. Because chipboard has no natural grain to resist the screw from withdrawing, these screws often have grippers around their head called nibs.