Check the listing for details. WESTWARD 53YV09 Socket, Steel, Chrome, 18 mm 53YV09. Condition: New. Listed at 6.47 USD. Socket, Socket Size 18 mm, 6-Point, Alloy Steel, Chrome, Deep, Hand, Drive Size 1/2 in, Metric, Impact Rated No, Bolt Clearance 12.4 mm, Standards ASME B107.110-2012 ½"-Drive 6-pt. Deep Socket features a restrictive interior shape with six meeting points. This means that only the correctly-sized socket will work for a particular bolt. The advantage of this is that a correctly-sized socket will fit snugly onto the bolt. This greatly decreases the danger of rounding the bolt's head with a socket. Deep sockets are better for specific jobs instead of general use. If you have bolted joints, they make a much better option for your socket wrench than shallow sockets. Deep sockets are better choice when the length of the bolt means the nut will need to go further into the socket.