(1) Characters
(a) The size of alphanumeric characters used for the indication shall be in principle 3mm. Square or larger.
(b) In case of forming or stamping, the depth or height of the letters shall be in principle 0.1 mm. or more.
(c) In case the space to indicate the material symbol is small, it is allowed to use a letter less than 3 mm. square, if the letter is visually recognizable, and it was approved by the customer.
(d) Use the larger characters is encourage depending on the size of the part, so that the letter may be easy to see.