The STANLEY FATMAX 3/8in M PRO-STACK 18-Piece Socket Set contains a selection of Maxidrive Sockets; with knurling to help take and use the socket easier. A neck-down design facilitates usage in restrictive environments. The Maxidrive profile maximises contact between the socket and nut, and visible dimensions to easily identify socket size. Fully connectable and compatible with the STANLEY FATMAX PRO-STACK storage system. Fixable to the larger PRO-STACK casing, this module offers a true mobile and secure solution for your mechanics tools. A transparent lid offers full clarity of contents; 1 x 3/8in Bi-material Ratchet 120 Tooth. 15 x 3/8in 6 Point Maxidrive Sockets: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19mm. 1 x 3/8in Extension 76mm (3in) . 1 x 3/8in Universal Joint.