Cutting perfect circles from Styrene.
Ever needed to cut a perfectly round circle from styrene and struggled??
Here is what I use for this purpose.
It is an Olfa Compass cutter and you is exactly like a standard compass, with the difference that you don't draw a line but scribe the styrene.
This is their small size sufficent for most modeling purposes, they also got a bigger one.
Fairly cheap item and comes with 5 spare blades.
Might come in handy for the armor guys and similar that need to cut templates for road-wheels, etc.
HTH.