The new generation for the Aramith Premium green box Premium set. With its Vitrotech technology, the ball surface is completely through-hardened giving it its unique transparent vitrified layer, increasing drastically the surface density and hence its longevity. No need for endless repolishing, no need for frequent replacement because of surface damage, but more important less need to replace the table cloth. That's right. Because the phenolic Aramith Premium balls resist optimally to the friction temperatures when the balls slip into motion, their surface won't rough up that easily and so they won't rough up your cloth either. And THAT makes a lot of difference! The Aramith Premium Premium sets still offer a lifetime up to 5 times longer than other materials. Each ball is controlled along 7 criteria: density, balance, diameter tolerance, sphericity, color, surface polish and brilliance. All numbers are engraved to very tight specifications. Aramith  Premium Balls.