The apps need to be played on either an Apple or Android phone with a diagonal screen size of 4.5 to 6 inches, as shown below:

Additionally the apps need to be viewed with a set of 3D VR goggles. We are not recommending specific brands, and we have no business relationship with any goggle makers or vendors. We do, however, recommend using goggles with built-in speakers so that your earbuds won't fall out of your ears in the middle of a hypnosis session. See the example below:

These goggles are a cheap commodity. Most are made by a handful of companies in the Far East, and they all do the same thing. To get the best possible deal, do this: Go to Google/shopping and enter the search term, 3D VR goggles with headphones. Then order the results by price from lowest to highest, and buy the cheapest one that resembles the above photo. Don't be surprised if you find prices below $10.00 for them.

If you have earbuds or earphones, and you are comfortable with them, then it's perfectly fine to use goggles without speakers, which are less expensive. Make sure, however, that the goggles have head straps.