A reward from completing the Level 3 upgrade mission. It appears as a matchbox-sized wooden cabin model that can be deployed into a 20-square-meter gray cabin with thick walls, metal-edged door frames and window sills. Upgraded functions include flood protection (honeycomb wall structure), fire protection (fire-retardant paint), strong corrosion protection (double-layered corrosion-resistant window glass), and a constant temperature system. Can be expanded by paying gold.
