If you have ever used a plunge cutting circular saw then you've probably clamped the rail in place to keep it from slipping. But clamping and unclamping takes time. What if you could use your dust extractor or vacuum to collect dust AND to hold the guide rail in place? You could if you had an Aerofix.
The Aerofix (F-AF 1 suction clamping system) is made by Mafell and is designed to work with their plunge cutting saws. It's a guide rail with a splitter fitting; one end of the fitting connects to the vacuum and the other connects to the saw. Air is pulled from the exhaust fitting of the saw and from the bottom side of the rail — so suction holds it in place.
The videos below show how it works. The first is from the manufacturer and is somewhat conceptual. The second is from a U.K. distributor and contains an actual demonstration.
If you are not familiar with Mafell, it's a German company that makes specialized woodworking equipment and power tools (saws mostly). It's high-end (expensive) stuff and is rarely seen outside of Western Europe — though the company does have U.S. distribution. The Aerofix does not appear on the U.S. distributor's website but if you wanted one badly enough they might be able to get one for you.