Stainless Steel Ruler 30cm/300mm with Protective Sleeve.
 
Constructed from sturdy stainless steel, this ruler is ideal for precision measuring with craft knives and cutting mats as well as pens and pencils. The inclusion of both metric and imperial scales allows for measurement in millimetres, centimetres and inches.
 
I use these for making direct measurements on spinning wood and also for any type of measuring where a measuring tape is unsuitable.  Great workshop tool!