Can someone help me identify this component?

Hi there,

I was tearing apart some old cordless phone transmitter and I came across this curious component I've never seen before.
It has 5 pins (red) plus 2 through-hole holders (green). It seems is screw-regulated as it has a hole on top like some potentiometers I saw.

I'd really like to know what can I use them for.

It's either a tuned circuit or a tuned transformer inside a metal screening can. The component betwen the green arrows is a ceramic capacitor. The screw on top moves the ferrite cap up or down a plastic core to adjust the inductance and hence frequency it is tuned to. The can style is standard, probably either 7mm or 10mm square but whether it is a single coil or a transformer will depend on how the wiring inside is configured.

They are re-usable but you need to know the frequency they worked at. If you carefully move the side of the can aside where the two small indents are on each side, it will lift off and you can remove the ferrite cap (it's brittle so be careful!). You can then wind as many turns as you like on the plastic core to make it tune to any frequency you like. Typically, the core will work best between about 0.5MHz and about 30MHz.

Brian.