Official match ball of the 1950 World Cup in Brazil
This ball was well-known as Super Duplo T
This model revolutionized the "technology" of manufacturing because it was the first ball which did not have any laces out the ball as past models. This ball was inflated like the current models. It had a current bladder/ valve. It was made of real leather.
Photo of the Brazilian team in the 1950 World Cup in Brazil
This model had the lettering of "SuperBall Double T" printed on its cover. On the photo above you can see a little bit.
Official poster of that time showing the Super Duplo T ball
Nowardays there are few models which hold still printed the lettering "Superball Double T", due to the time the lettering is gone like the photo below.
The ball was less dangerous to be beaten with head due to it did not have any laces out. With older models players could have serious injury in their heads when they hit the ball with the head. Even they could bleed.
Although the Super Duplo T ball also consisted of 12 panels, do not be confused with the 1930 twelve panels ball. There are two big differences, the first one is that the ball had a sewing with laces out the ball to access and to inflate the bladder. The second difference was that its panels were sewed in a intertwined way. Please see the picture below.