Can you use tek screws in concrete?

No. The point is cut for steel and blunts straight away in masonry. For concrete, brick or block you want concrete screws, which have a hardened thread made to cut into a pre-drilled hole.

Can you use tek screws in wood?

Not a standard one. Metal to wood screws fix thin sheet steel, up to 0.8mm, down onto timber using a slash point, and they work in timber on its own too. Fixing timber onto steel takes a wood to metal screw. Please note that they will not work if the materials are the other way round, i.e. fixing metal to wood.

Self Drilling Screws - Countersunk Phillips

These countersunk Phillips self-drilling screws are used when fixing into PVC or aluminium window frames. The screws are 3.9mm in diameter with various lengths available. They are used to fasten different types of hardware to the frame where steel or aluminium reinforcement is present.

Self-drilling screws are a type of self tapping screw with a drill point at the end. This eliminates the need for a hole to be pre-drilled and enables the fastener to be fixed in one operation.
The drilling point of a self-drilling screw is given a number - the higher the number the thicker the material it is able to self drill into.

As a guide if you don’t know the number of the drill point on the screw you can measure the length of the drilling tip and this will give you an approximate maximum thickness of material it can drill through. We would recommend caution when using this method as if the thickness of the material being drilled exceeds the length of the drilling tip it can cause the screw to jam and tear the head off – it is always best to err on the side of caution.