I went to 3 shops, but nobody knows it!
Their website is by far not clear, but it is an option for the Prepaid Wertkarte 6,8ct or the Vielwert - Wertkarte. The option can be renewed also before the end of the 30 days period of validity, if the 1GB has been used. Then another 30 days period begins.
http://www.bob.at/final/de/Media/PDF...tkarte_1GB.pdf
According to the decription upload speed is only up to 384kBit/s which is much slower than my experience with bob "contract" data SIMs. These reached about 2 MBit/s upload speed.