Gearwrench KD84926N 0.38 in. Drive Impact Locking Extension Set, 4 piece Slide Locking Mechanism Securely Attaches Socket to Extension. Made From Chrome Molybdenum Alloy Steel for Exceptional Strength and Durability. Manganese Phosphate Coating for Corrosion Resistance. High-Visibility Laser Etched Markings for Quick Size Identification. Includes Vacuum Formed Storage Tray.