The
Aperture science handheld portal device(
ASHPD)is a device found in the puzzle game created by Valve , portal and
portal 2.It's used to create two portals, when you enter one,you come out of the other one.This device is used to solve diffrent, easy and difficult puzzles.
Ummm....
Just go and play
portal 2 to see the handheld portal device.(it's amazing)