The FL-T800 is the largest size 1 (1.25 m diameter) liquid fuel tank, at 3.05 m tall. Along with the FL-T400 Fuel Tank, they are the only fuel tanks in the demo. As per the name, it contains 800 units of propellant for liquid fuel engines. Aside from the different dimensions and weaker connections, this tank is identical to the X200-8. It is slightly cheaper to use a an FL-T800 in place of the equivalent mass of FL-T100/200/400 tanks, though performance is identical.
There are two labels on the fuel tank that read "BC 0003" and "KB 6551".
KB for kerbal. The numbers just make it look sciency.
|| A stretched variant of the FL-T400, the FL-T800 holds twice the fuel in a slightly stronger container. The black stripes along the side make the rocket go faster, our engineers tell us.