Also, an interesting note on the above-mentioned weapon: It is also known as the Zeropoint Cannon.
This is a reference to zero point energy, as the cannon makes use of real-life (although questionable and scientifically unproven) Hutchinson Effect, which is a very complex way of saying that it makes stuff hover using space energy.
The Zeropoint Cannon is not to be confused with the Zeropoint Gun, a smaller Half-Life 2 weapon of similar design, which can pick up and swing stuff around at long-range. It can also glue objects together with an effect akin to static cling.
This gun also makes use of properties of the Hutchinson Effect.
These weapons can be differentiated by the colour of the energy effects they use. The Manipulator is orange, while the other is blue.