M8 x 15.5mm Knurled Reduced Head Countersunk Rivet Nuts - A2 Stainless Steel: Accu.co.uk: Hardware
Amazon.com: Novus 045-0077 Blindnietmutter A9 Blind Diameter 9 mm Aluminium 30 Rivet Nuts M6 Thread 15 mm Length for Plastic and Lightweight Construction Materials, Silver, Stück : Industrial & Scientific