Very noticeable - these two toned plaques, with a blue or grey sidebar - pop. We generally prefer to sand carve them from the back leaving the front smooth as it gives the etching more depth but, with this piece, as you see in the photo, a mix of front and back paint-filled and not can be very cool. Comes in a presentation box.
The answer here could be a long article but in general, a rotary engraving machine is driven by compressed air which pushes a diamond or carbide tip into…