PRECISION ANGLE  GAUGE BLOCK are designed for 
  intended for the control and graduation of goniometric devices and angular templates, and also for check of corners of products.

Made of hardened stainless steel.
The maximum deviations of the working angles are:
  ± 8 arcsec.
 I am always ready to answer your questions honestly and impartially.
Discount for the combined shipping

I will add a tracking number in EBAY