"All LOK-ON™ Impact Sockets are manufactured from 42CrMo4. Chrome Molybdenum is an industrial grade material designed for impact and extreme torque applications. Standard 50bv30 CrV sockets are not designed for impact use and may shatter and cause personal injury if used for impact. LOK-ON™ Impact Sockets are finished in black phosphate for superior corrosion protection and are stamped and laser etched for easy size identification. LOK-ON™ Impact Sockets will perform better, last longer, save time, reduce wear and replace the need for fastener extraction tools.