12 point flank traction profile according to DIN 3124 / ISO 2725 internal square to DIN 3120 / ISO 1174 with ball reception for manual operation matt finish chrome vanadium 12 point flank traction profile according to DIN 3124 / ISO 2725 internal square to DIN 3120 / ISO 1174 with ball reception for manual operation matt finish chrome vanadium