Certified Stainless Steel Scales are each individually marked with a unique serial number and packaged with a certificate of accuracy with the same serial number as the ruler. The certificate of accuracy is traceable to NIST (National Institute Of Standards and Technology). These certified rulers are suitable for use with most quality programs such as IS09000 that require certified measuring tools. The certified rulers are single sided featuring an inch scale in 1/32" and a metric scale in mm. The certified rulers are 1" wide, 0.030" thick and manufactured from stainless steel. They are engraved and have black filled graduations and graphics. Each certified ruler has rounded safety corners and a convenient 1/4" diameter hang hole at one end. Not flush starting. 6" Scale