Super lock sockets which are very handy for removing stubborn worn or rusty nuts and bolts. The more pressure you put on them the more they will grip the nut or bolt. Manufactured from Chrome Vanadium These also have knurled ring which greatly helps to grip them when they have grease and oil on them Specifications: Chrome Vanadium Super lock Polished and satin finish Knurled grip Professional quality 3/8’’ and ¼’’ drive Bespoke plastic tray Sizes: 3/8" Drive, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm 1/4" Drive, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm