304 stainless steel, rivet nut, vertical pattern pull cap with flat head, small rivet nut with countersunk head. : Amazon.de: DIY & Tools
Amazon.com: uxcell M8x1.25mm (Pack of 30) 4 Pronged Tee Nut T-Nut for Table Legs Rock Climbing Wall Woodwork Holds Wood Cabinetry : Industrial & Scientific