Vanquish Products Scale Hardware Tool Tip for 1-64 and M2 scale hardware (VPS01710, VPS01711, VPS01712, VPS05002, VPS05003, VPS05004)
Tool shaft diameter is 4mm
Hex shape on tool shaft is made to work in conjunction with standard "cross wrench".
Also compatible with Vanquish Products 1/4" Tool Adapter, VPS08430