The KT Pro Universal Impact Socket Sets, Nos. 4440SP and 4450SP, are designed to allow greater access in confined working environments. Each socket is constructed with high quality chrome molybdenum alloy steel and is heat treated for improved strength. These sockets are available in two set options: deep universal impact sockets (No. 4440SP) and standard universal impact sockets (No. 4450SP). Both sets come with large markings for easy size identification and a lifetime warranty.