This complete vac grit guard assembly is for those customers who had early MAG-9000 series sharpeners, and would like to upgrade to the latest design. Or perhaps just need a replacement. In 2004 the vac grit guard became OEM. In 2010 the 9000-50 grit guard evolved again, the grit guard has increased in over all size to better contain sparks. Early MAG-9000 series units (1987-2004) had a simple grit guard without a vac attachment.