They show up as either "vias" or "hollow grommets": < https://www.ebay.com/sch/Other-Fasteners-Hardware/42905/i.html?_from=R40&_nkw=vias > < https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.H0.Xhollow+grommet.TRS0&_nkw=hollow+grommet&_sacat=0 >Roy