The device called Sausage, detonated in the Mike test was the first true thermonuclear bomb ever tested.
However, the Sausage was not a deliverable weapon. It was an enormous, complex device, 80 inches wide and 244 inches long.
The entire assembly weighted 82 metric tons. Sausage was built using Teller-Ulam principles of staged radiation implosion.
Interestingly Teller himself didn't participate in development. Los Alamos Panda Committee, directed by J. Carson Mark did
the job. TX-5 fission bomb was used as a fuse(primary stage). Super cooled, liquid hydrogen was used as a thermonuclear
fuel. The Cab, building which was housing the device was located on the zero island. A plywood tube was
assembled from the Cab to the furthest island, where the detection station was, some 2 miles away. The tube was filled with
Helium, to allow radiation rays travel faster before it was consumed by the fireball.
The explosion yielded 10.4 Mgt. Mike's fireball measured 3 miles. The cloud formed by Mike shot was immense. Stabilized, it reached 135 000 ft high, and stretched 60 miles in diameter, which eventually spread over 1000 miles.
Mike destroyed the entire Elugelab island. The crater formed as a result of the explosion measured 6240ft(1.5Km) across and 164ft(53m) deep. Following the test, high levels of radiation covered most of the Enwetak atoll.
This was 4th largest test ever conducted by US, (the largest at that time). For comparison, this is more then all allied bombs dropped during WW II together.