Enhanced European Test Piece is designed for routine testing of x-ray machines, and it does contain samples of materials of varying density.

The Enhanced European Standard Test Piece (STP) is manufactured in Europe to comply with the EU Commission decisions and requirements laid down by European Civil Aviation Conference (ECAC) and may be used within European Union countries.

In addition it does comply with the U.K. Home Office, Department of Environment, Department for Transport and regional specifications, for use in support of the UK Transport Security Programme for enhanced airport x-ray equipment.

In EU and various non-EU countries it is now a legal obligation to regularly test image quality of security x-ray screening equipment.