Of the two gray markers available, this one has a slightly bluer hue than the other one! That makes it more mechanical, we suppose.
Gundam Marker - Gundam Gray GM12
Gundam Marker HobbyOne Japan
GSI Creos: Gundam Marker - Mechanical Gray GM13 - Vagabond Games & Collectables
BANDAI NAMCO Entertainment GM12 Gundam Gray Gundam Marker, GSI : Arts, Crafts & Sewing
GSI Creos Mr.Hobby GM13 Gundam Marker MECHANICAL GRAY (Color Pen) - Plaza Japan
Gundam Planet - Search results for: 'mechanical combat bring 1 100
Gundam Marker - Gunze Sangyo - Farby i chemia modelarska
GSI Creos - Gundam Marker: Mechanical Gray #GM13 GNZ-GM-13 [4973028935936]
Gundam Marker Gundam Mecha Gray (GM13) - Canada Gundam