Adding more RAM and otherwise changing stuff inside your computer first requires you to actually unscrew the device. And, if, like me, you have rather big not so deft hands then the screwdriver can make a big difference to the speed of doing that. I'd really like something with a magnetic tip (is that possible?) so that it can "stick" to the screw I'm getting out. Then, when I've unscrewed it, I don't drop it on the carpet and have tp s[end ages looking for it. I'm also wondering what sort of size screwdrivers I need for different Macs. So my 2009 iMac and 2011 Macbook Pro. And, for the record, what size would I need to get the screws out of my iPhone 3GS when I decide to get a 4S? Any advice is much appreciated.