Many of the less expensive small size (# 1 head) Phillips Head (PH) driver tips are not manufactured to tight tolerances to match the PH screw head socket although that is not necessarily apparent to the naked eye. However, if the user attempts to remove stubborn, rusted, corroded (dissimilar metal corrosion) Phillips Head fasteners with an inferior tool, the frequent result is that the socket in the head of the Phillips screw will be stripped or the flutes on the driver end will be damaged. Typically, the screw is rendered non-removable without incurring collateral damage to the surface being secured with the fastener. The Xcelite driver tip, on the other hand, fits the PH socket in the head of the screw more precisely and with appropriate care, will remove the screw without damaging the screw head, the tip of the tool, or the item’s surface. If any of the nasty conditions mentioned above exist, don’t damage what you’re trying to fix. Get an Xcelite driver with great “bite”, use an appropriate penetrant if needed, keep the tool aligned with the fastener on the screw head, apply shock and then torque. Good luck.