For all the machinists, toolmakers, and quality control professionals out there - this HHIP granite surface plate is serious business when it comes to precision measurement. Measuring 18 x 12 x 3 inches, this Grade B surface plate gives you that perfectly flat reference surface you need for accurate inspections and measurements. The accuracy is impressive at +/- 0.0001 inches, and each plate is carefully checked using an auto-collimator to ensure it meets those tight tolerances. Made from high-quality granite, this surface plate meets or even exceeds Federal Specifications GGG-P-463C, so you know you're getting professional-grade equipment. The ledge-free design (ledge 0) gives you maximum usable surface area for your work pieces. It comes with a certificate of inspection too, which is crucial for maintaining quality standards in professional settings. The granite material is naturally stable, wear-resistant, and not affected by temperature changes the way metal surfaces can be. Whether you're setting up a new workshop, replacing an old surface plate, or adding capacity to your quality control department, this plate delivers the precision and reliability you need. The weight and construction provide excellent stability during use, and the overall craftsmanship is exactly what you'd expect from HHIP's professional tools. It's one of those foundational pieces of equipment that every serious machine shop or inspection department needs. The value for the quality is seriously impressive - this is professional-grade precision at a very reasonable price point. Your measurements will thank you!