ZAG - Zavod za gradbeništvo Slovenije - Slovenian National Building and Civil Engineering Institute - located in Ljubljana.
From Zag web site: ZAG is the leading Slovenian Institute in the field of building and civil engineering.Through high-quality work it successfully promotes the progress-orientated Slovenian applied science and technical expertise on a global scale.
As a certification body, ZAG’s Certification Service (CS ZAG) places great emphasis on the continuous improvement of the quality of its services. For this purpose it has established its own quality management system which meets the requirements of the standards SIST EN 45011 and SIST EN ISO/IEC 17065, whose fulfilment is confirmed by internationally acknowledged accreditation.
The web site of the institute that issue the Standards stamp http://www.zag.si/en
An example of a cover that carries the standard on the "ultimate manhole covers" site. From this lid the picture that appears in the general section was taken.