The new special holder, to be used with 9 pz, resin diamond discs, 3”-75mm. The “Spring holder system” is developed for grinding and polishing any kind of concrete floors. Thanks to the smart design, installed on the grinding machine, it allows to achieve a perfect and homogeneous result, even if the floor is not perfectly flat. This is possible because these discs are pushed by the springs through the small depression that may be present in the floor.