Ruroc Atlas 4.0 carbon fibre Superman helmet. The size is Ruroc's S/M size. Which according Ruroc will fit a head measurement of 55.5cm to 57.4cm. With a fabric measuring tape, wrap it around your head just above your eyebrows and ears. Pull the tape comfortably tight.
Repeat once more and go with the largest reading. Comes with a CLEAR visor only (The dark visor seen in the borrowed pics from the Ruroc website is not included).