Crescent 121-piece professional tool set contains a carefully selected assortment of Crescent brand hand tools needed for most industrial, mechanical, and consumer applications. The set includes 1/4" and 3/8" drive quick-release ratchets with a wide selection of standard and deep sockets in the most common SAE and metric sizes. Included in the set are the following 3/8-inch drive tools: a 60-tooth quick-release ratchet drive, 3-inch extension, 23 twelve point sockets and 12 six point deep sockets (SAE and metric). It also includes the following 1/4-inch drive tools: a 60-tooth quick-release ratchet drive, a 1/4-inch bit adapter, 23 six point sockets and 12 six point deep sockets (SAE and metric). And an acetate magnetic bit driver with 10 driver bits and 12 hex nut setter bits (SAE and metric). 24 hex keys with tilt-out caddy in both SAE and metric are provided as well. All tools in this industrial quality tool set meet stringent new ANSI and ASME specifications and come with a full satisfaction .