The Exotek Hudy/Protek Metric Hex ID Collar Set is a handy identification collar set that can be used with most brands of hex wrenches including Hudy, Protek, Associated, and more. When all of your wrenches looks the same, these color coded collars will help you to quickly identify the size you need. The collars are engraved with 1.5, 2.0, 2.5 and 3.0 sizes to suit the most common metric wrench sizes. The collars use 2mm set screws to secure them on the tool tip, and a .9mm Allen key is included to make installation easy.