1)Flange Nut DIN6923 (Hexagon nuts with serrated flange ISO metric coarse pitch thread; )
2)Available Size: M2 to M20
3)Class: 6,8(6S), 8, 10
4)Material: low carbon steel or mild carbon steel, according to customer's requirement

The design for the flange head could be serration or without serration and your special requirment aslo could produce according to your drawings.