What is this kind of screwdriver called?

[Liam]

I am trying to take a broken coffee maker apart, and in the base there are four screws; the head of each screw looks like this:

|S| |L| xxx xxx xxx |O| |T|

Where xxx represents where the slot isn't cut through, and | | represents the slot. You'd need a standard slotted screwdriver with a sort of a nibble taken out of the middle of the slot. What's that kind of screwdriver called?

Thanks Liam

[Liam]

I've found it here:

I am trying to take a broken coffee maker apart, and in the base there

[nothermark]

check harbor freight if there is a store near you - they have a cheap kit of security screw bits. If they are round head screws I have used small vise grips in the past.