On the control switch you should see "auto off" and "stay-on" on a pad where you can over-ride the automatic shut-off. You can select either one to have the pad either shut off in two hours or to stay on until you decide to turn it off yourself.
There are pads that do not have the "auto-off" feature. You can still buy these. They are the ones that usually have just three settings or even just one setting. If it doesn't say "auto-off" on these pads, the pad should remain on.
But you should test it. Check a clock when you plug it in. Two hours later, if it hasn't shut off, you have confirmed you have a pad that will remain on.
There are pads that do not have the "auto-off" feature. You can still buy these. They are the ones that usually have just three settings or even just one setting. If it doesn't say "auto-off" on these pads, the pad should remain on.
But you should test it. Check a clock when you plug it in. Two hours later, if it hasn't shut off, you have confirmed you have a pad that will remain on.