Unique spiral hole arrangement - minimal clogging and maximum grinding effect Hookit attachment system Quick disc change - no need to align holes Efficient extraction system - significant dust reduction in the environment The wide range of 3M abrasive discs has been enriched with new Blue multi-hole discs in grits from P80 to P600. Increased grinding speed and efficiency are the result of a unique spiral hole pattern, which, combined with a new universal backing pad, ensures excellent dust extraction efficiency during grinding processes. All these technologies, along with the enhanced quality of the applied coating, make the "Montana" series discs at least 30% more effective in grinding. The Blue 3M Hookit 325U abrasive disc is an aluminum oxide-based product designed to provide excellent finishing and very good dust extraction thanks to the multi-hole technology. Increased grinding speed and efficiency are the result of a unique spiral hole pattern, which, combined with a new universal backing pad, ensures excellent dust extraction efficiency.