The performance and life achieved by abrasive discs is highly dependant on the backing pad. A worn or unsuitable backing pad is likely to result in uneven wear on the disc, usually showing with a worn edge and relatively unused middle. In general it is better to chose a firmer backing pad for coarser grades and where more pressure is being applied, and a softer one for finer grades and where edge gouging is to be avoided. For grip discs it is important to choose the correct backing pad. Grip sanding discs use relatively short hooks, whilst surface conditioning need longer hooks. Trizact discs are most commonly used on flat work and we recommend the VEL/VZ backing pads to get the best life and results.