A screwdriver is just a screwdriver right? You either need a flat head or a cross head...
Well no and as you find with a lot of mechanical engineering its linked to the development and evolution of various standards.
What most people know as the flat head screwdriver (technically a Slotted head) was the first system of applying torque to turn a screw fitting. They work but have a tendency to both strip the slot and slip, causing potential surface damage. If you are looking for a good quality slotted screwdriver you can find one here.
The Philips (cross head) pattern was designed to address these issues. They were easier to locate the driver into, less likely to slip and with the larger surface area of the cross shape less likely to damage the head. It was a significant step forward and most applications switched from slotted to Philips.
But here's were the confusion comes in - there's another type of cross head pattern that has widely replaced Philips. It's called PoziDrive and the difference isn't easy to spot straight away but using the right screwdriver is important.
Look for small lines splitting the quarters of the cross. If you see them then its a Pozidrive screw head.
If you are using modern wood screws they are likely to be PoziDrive. If you are working on old machinery or electronics then they could be Philips.
This is were this King Dick 1 for 6 screwdriver comes in very handy. It uses a patented head shape which means it can be used on not only both Philips and Pozidrive, but also each of the three most common sizes.
Can be used on PH1, PH2, PH3, PZ1, PZ2 and PZ3.
That makes it amazingly useful to have in the tool kit as it covers most options. The design is a compromise. Perfect for working on a couple of screws but if you know you are working on multiple screws of the same size then it's worth searching the tool box to find the specific sized screwdriver for the job.
** There are other cross head screw patterns out there, but they are far less common to come across. If you work on vintage (maybe pre 70's) Japanese motorbikes they used a pattern referred to as JIS. They look similar to Philips but the use of a Philips screwdriver will eventually damage the heads. Although not designed for these we've had feedback that this screwdriver works well with JIS heads.