The number of allowed F1 TV Pro simultaneous streams depends on the subscription plan purchased. The standard subscription plan allows for 2 simultaneous streams, while the Premium subscription plan allows for 4 simultaneous streams. Additionally, both plans allow for unlimited devices to be registered on the account, so users can switch between devices on their account without any extra charges. For example, if you purchased the standard f1 TV Pro subscription plan, then you would be able to watch two streams at the same time on two different devices. You could watch one stream on a tablet and another on a laptop, or watch both streams on the same device, such as a television. As for the Premium subscription plan, it would allow you to watch up to four streams at the same time on four different devices. This means that you could have four different family members or friends watching four different streams on their own devices. To summarize, the standard f1 TV Pro subscription plan allows for 2 simultaneous streams and unlimited devices, while the Premium subscription plan allows for 4 simultaneous streams and unlimited devices.