M4x6 Button Head Socket Cap Screw
For use or compatible with:
TACAMO Type 68 I with Under Folding ButtstockWood Buttsock
TACAMO Type 68 II with Polymer Side Folding Buttstock
TACAMO Type 68 III with Side Folding Buttstock
TACAMO Matador I with Under Folding Buttstock
TACAMO Matador III with Side Folding Buttstock
For better image of diagram find it here.