The screw bits in our iFixit bit kits have engraved prefixes that indicate the head type. These prefixes are typically followed by a number that indicates bit size. For example:

PH2 - (Phillips #2) A large Phillips bit.

PH0 - (Phillips #0) A medium Phillips bit.

PH000 - (Phillips #000) A small Phillips bit.

Choose the bit size that fills the screw head entirely. A bit that is too big or too small will not seat properly, and you'll end up with a stripped screw.