About Anti-Camout Ribs, ACR
ACR Information - Anti-Camout Ribs
ACR stands for the "anti-camout ribs" that are formed on screw driver tips

and may also  occur in screw sockets.  The ribs adhere securely to screws to minimize

camout while reducing worker fatigue. ACR drivers can reduce camout by 30% to 40%.
ACR Information - Anti-Camout Ribs