Metric Hex Coupling Nuts. These DIN 6334 nuts are made from 18-8 (A2) stainless Steel. Nuts are standard Coarse thread which is standard for Metric fasteners.
Size (AF = Across Flats, L = Length):
M5-0.80 x 8mm (AF) x 15mm (L)
M6-1.0 x 10mm (AF) x 18mm (L)
M8-1.25 x 13mm (AF) x 24mm (L)
M10-1.50 x 17mm (AF) x 30mm (L)
M12-1.75 x 19mm (AF) x 36mm (L)
Nut Size is the size of the screw that the nut is for (Example: M8 nut for an M8 screw).