According to this:
http://www.manualsdir.com/manuals/650195/ofna-racing-picco-26-max.html
They are ofna part # 51331:
https://www.nitrohouse.com/Picco-Head-Screws-25x14mm-2126-Maxx_p_8741.html
Which are M2.5 x 14mm cap head screws.
www.mcmaster.com
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