Design
The AntVR headset looks pretty big, but thanks to a folding design actually takes up less space than a cardboard Google Cardboard headset. Still, it's not exactly something that you can slip into your pocket, though an included pouch means that you should feel okay about keeping it in your bag.
The design is familiar enough if you've used other Cardboard headsets - there's a clasp on the front for your phone, lenses in the back, and a nose rest. This particular headset uses a hinged design for the front, that folds up when not in use. The top hinge is spring-loaded, which means that it will hold your phone securely in place when in use, but this also means that it is extremely difficult to attach the phone to the headset. It would take multiple attempts and a full minute to get the phone to sit securely in place even after a whole week of using the headset.