It extrudes selected faces.
It pushes out with 
dragging to the right, and dents with dragging to the left with pressing the left button.
This command is similar to [Menu > Selected > Extrude faces] but this can input the amount of extruding visually.
There are two modes; [Normal] and [Bevel].
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| Original | [Normal] | [Bevel] |
It makes new joined faces when two selected faces are joined.
You can select from 4 types how to round the border of the selection part.
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| Original |  |
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It makes new separated faces even if two selected faces are joined.
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| Original | ||
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| 0 degree | 45 degrees | 90 degrees |