This quality mark of Dutch origin belongs to Stichting Bouwkwaliteit, which delegates management, among other things, to SKH (Stichting Keuringsbureau Hout).
It certifies that the products comply with the specific requirements defined in the National Assessment Directives. For plywood, the relevant directive is BRL 1705. 

This directive mainly concerns the following requirements:

• Thickness of the plies in the panels and species,
• Gluing performance,
• Face appearance classes,
• The control operations implemented by the manufacturer (or distributor).

The product quality requirements are slightly higher than those applicable to CE marking.

Most of the throughout-okoume plywood panels with exterior gluing in the PLYSOROL range have been awarded KOMO certification (certificate no. 32517).

NB : The BRL 1705 directive distinguishes 13 plywood panel classes (A to M)