you can install it on as many computers as you want....but it will only start up and run on a computer that has a registered iLok with a PT license on it. If you have your iLok in your main DAW, then decide you want to do some on location recording with your laptop, you will have to remove the iLok from the DAW and put it in your laptop to make PT open on the laptop. While the iLok is in your laptop, you will be unable to access PT on the DAW.