This radiopaque extremity ruler is manufactured from a high performance, chemical-resistant plastic which can be sterilized using ethylene oxide or alcohol. Unlike acrylic rulers, this ruler is very flexible and virtually unbreakable. These scales are used whenever measurements or locations in the image field are required. 1 cm and 0.5 cm graduations are engraved at least 0.030" deep and filled with a special, flexible radiopaque material to give distinct and permanent readings on the radiograph. 115 cm lengths are available in two thicknesses (1/16" and 1/8"), and All Craft also manufactures 45 cm flexible scales (1/16" thick).