What can the second nozzle do that one nozzle can't?

It can print a model in one material and soluble or breakaway supports in another, or two colors in the same job. That avoids swapping spools mid-print and gives cleaner support removal.

Which filaments does the heated chamber help with?

It mainly helps warp-prone engineering plastics such as ABS and ASA by keeping the air around the part warm. PLA and PETG print fine without it.

How big is the build volume?

256 x 256 x 256 mm, a cube. That fits most functional parts and multi-part plates, though very large single pieces still need to be split.

Does it calibrate itself?

It runs automatic flow dynamics calibration, and AI failure detection watches the print for problems. You still level and maintain the nozzles as with any dual-nozzle machine.

Is it a good first printer?

It is more machine than a beginner needs. A single-nozzle printer is simpler and cheaper to learn on; the X2D pays off once you want multi-material or high-temperature prints.

What comes in the box?

The printer, its dual-nozzle head, the touch screen and the usual startup accessories. Filament and multi-color units are typically separate, so check the listing's included items.