So for laptops, the hollow side faces up. The two little holes on the top let you see if it’s hollow or solid. Works in all the devices I’ve tried. Obviously doesn’t help in the dark, but this has saved me so much time so far.
Edit: For vertical ports: So for laptops, the hollow side faces up. The two little holes on the top let you see if it’s hollow or solid. Works in all the devices I’ve tried. Obviously doesn’t help in the dark, but this has saved me so much time so far.