Most modern paragliders have some sort of rigid inserts in the leading edge. In order to protect these inserts the gliders should be packed "accordion-style", and this bag helps you get it right every time, regardless of the surface.
Note that the chord of your paraglider decides the size of Protec bag you need. If you own a beginners' or intermediate wing, chances are your chord will be more than 2.70m and you will need the L size. If you fly an advanced wing with high aspect ratio, chances are your chord will be 2.70m or less and you will need the M size.
The L size Protec bag is 3.30m long and will hold even large beginner wings.
In order to help you choose a Protec bag for your UP wing, or for a wing from any other manufacturer, click here for some tables you can use.