If you're trying to remove big, old philips head screws - such as the door striker plate in an old car - just buy this tool and don't look back. It works - end of discussion! Using this tool is very simple. Here's what I did to break loose the screws in a 35+ year old door striker plate: 1. Use the biggest philips bit that will fit snugly into your philips head screw. 2. Get a large hammer, preferably a small sledge or big heavy claw hammer 3. Use a pencil to lightly mark the the screw head with the surrounding material (so you can see when you start making progress) 4. Insert the tool into philips head screw and TURN IT THE DIRECTION YOU WANT IT TO GO - it will only move a little, maybe 10-deg or so rotation 5. Hold the tool firmly and give it a good solid whack with your hammer (yes, it will bounce out of the screw head - this is normal) 6. Check your mark to see if the screw moved (it feels great to finally see progress!) 7. Repeat until the screw has rotated about 45-deg (1/8 turn) 8. Using the TOOL, see if you can turn the screw BY HAND 9. If you can't turn it yet, repeat steps 4-8 until you can back out the screw by hand I'm sure it works for other purposes, but this one use was enough to justify the purchase for me.