18. GRSP also noted ECE/TRANS/WP.29/GRSP/2021/15, amended by GRSP-69-18 aimed at preventing the issue of invalidating a UN Approval with the use of an aftermarket product. The proposal received some comments from the experts of Euromed (GRSP-69-26) and proposed changes from the expert from Italy (GRSP-69-32). GRSP Chair and the Chair of the ad-hoc group proposed to convey the above proposals into the activity of the ad-hoc group on safety-helmets. The expert from Euromed argued that the for sake of transparency it was advisable to establish an informal working group (IWG) and he introduced the terms of reference of the IWG (GRSP-69-36). However, concerns were expressed about the number of interested experts and about the need to be much more responsive in providing a possible solution to the December 2021 session. Following the suggestion of the expert from the Netherlands, GRSP agreed to continue the activities of the ad-hoc group and requested the secretariat to provide a wiki page on the ECE website. In the meantime, it was clarified that rules of procedure of IWGs, ad-hoc group, Task Force shall be the same of those of parent group. Accordingly, GRSP reminded all the Chairs and secretaries of the above-mentioned groups to verify consistent credentials of attendees and receive copyright disclaimers for documents posted on UNECE website. GRSP agreed to resume the discussion on this subject waiting the outcome of discussion of the ad-hoc group on ECE/TRANS/WP.29/GRSP/2021/15, GRSP-69-26, GRSP-69-32 and GRSP-69-36.