...The one that's hard to get is the System Zero. This looks like an inverse torx (The screw head is male, with slots round the outside, the driver is female), but it's designed so that nothing but the right tool will get it out (the sides of the screwhead taper slightly so that you can't grab it with pliers or a Mole Wrench (self-locking wrench), for example). Yes, I have a set of those tools -- one of my EPROM programmer [1] is assembled with them, for what reason %deity only knows. [1] A thing called a Ferret. It's a combined EPROM programmer, breakout box, RS232 / current loop / centronics converter, Z80 computer, strip printer, etc in a portable case.