2-Point Inside Measuring Instrument Range 4-6.5" Graduation .0005" 511-744-20This is a short range application Bore Gauge Set that automatically self centres via a centring bridge and offers you the following benefits: It reduces the influence of heat from the operator's hand by 50% by making the grip hollow structured, thereby retaining high accuracy measurement. Interchangeable washers (0,5 mm thick) are supplied as standard accessories, so you can enable setting in small steps. Contact points are carbide (>18 mm range),