I had one of those prints for my background for a while.
Midbulk transport, standard radion-accelerator core, classcode 03-K64, Firefly
According to the blueprints, Serenity was laid down in August 2459. The ship is 269 feet (82 m) long, 170 feet (52 m) at its widest point, and stands 79 feet (24 m) high when landed. Serenity weighs 282,500 pounds (128,100 kg), is capable of carrying 164,900 pounds (74,800 kg) of cargo and 18 passengers, can achieve an acceleration of 4.2 g, and has a maximum range of 440 astronomical units when carrying minimal cargo.