I had no idea Robertson still existed. I received a box of them for free when they were [Edit] being pushed in the 80's and loved them. The screw would stay on the bit no matter what angle I held the drill which made putting screws into hard to reach places super easy. No need for magnetic bits or other tricks. The local stores only carry Phillips, Hex and Torx so I buy Torx for the smaller screws and Hex for the bigger fence post screws.