Features and Benefits: Forged from high quality chrome-molybdenum alloy steel for long lifeEach impact socket features a radius corner design, causing the socket to grab the sturdy wall of the fastener instead of grabbing the cornersPackaged in a durable heavy duty blow mold caseSet includes the following metric impact socket sizes ranging from 10mm to 36mm This is a 26-piece Impact Socket Set. It is metric in size. It is 1/2 in. drive. WARNING: This product can expose you to Nickel (Metallic) a chemical known to the State of California to cause Cancer. For more information go to www.P65Warnings.ca.gov.