Specification Brand : HHIP BulletPoint1 : The top surface of this plate is precision ground to achieve a high degree of flatness and the accuracy is +/-.000050". It is a Grade A (Grade 0) plate. BulletPoint2 : Granite surface plates meet or exceed Federal Specifications GGG-P-463C and it includes a certificate of inspection. (Note that these are not NIST traceable.) BulletPoint3 : Granite plates are used for measuring the flatness and squareness of other objects, laying out parts, calibrating instruments, setting up tools, checking parallelism and perpendicularity, and measuring heights with the use of a height gage. BulletPoint4 : They are also used as a work surface for assembling, inspecting, and marking parts. Non-magnetic and non-conductive. Harder than steel and does not nick or burr. BulletPoint5 : Surface plates are offered by HHIP in various sizes, with different levels of flatness and accuracy and are checked by an auto collimator for overall accuracy assurance. BulletPoint6 : Compact Size: Compact 3" diameter and 1.5" height make it portable yet stable for precise work. BulletPoint7 : Durable Construction: Made to withstand heavy-duty use in machining and workshop environments. BulletPoint8 : Ideal Addition: Perfect for machinists, hobbyists, and craftsmen needing a reliable workholding solution. CustomerPackageType : Standard Packaging ExternallyAssignedProductIdentifier1 : 769053049908 ExternallyAssignedProductIdentifier2 : 0769053049908 ExternallyAssignedProductIdentifier3 : 00769053049908 ItemName : HHIP 4401-1812 Black Granite Surface Plate, Grade A, Ledge 0, 18" Length x 12" Width x 3" Height, +/000050" Accuracy, 80 lb. Weight ItemPackageDimensions_Height : 50.038 centimeters ItemPackageDimensions_Length : 10.16 centimeters ItemPackageDimensions_Width : 30.734 centimeters ItemPackageQuantity : 1 ItemTypeKeyword : calibration-surface-plates Manufacturer : ABS Import Tools, Inc. ModelName : CRISANDcgba7oufhx ModelNumber : 4401-1812 NumberOfItems : 1 PartNumber : 4401-1812 ProductDescription : Features: 1. 100% brand new and high quality 2. Made of high quality carbon steel material, to use. 3. Mainly used to place circular workpieces such as shafts, sleeves, discs in order to find the center line and draw the center line 4. It is an important auxiliary tool in platform measurement 5. Suitable for inspection, lining, positioning of accuracy shaft parts