6" H & L Zirconia blend discs for intermediate and fine sanding. Greenguard. The Bona Abrasive line provides the most aggressive and lonest lasting abrasive in the industry, without sacrificing smoothness to achieve the best surface for staining or finishing. Get maximum efficiency and stay on the leading edge of technology with Bona Abrasives. Feel the difference with unsurpassed performance and value on every job.