According to GizmoChina, based on the names, it is safe to presume that these are foldable and rollable devices.
The NEX Fold should have a similar form factor to the Galaxy Z Fold 2 or Mi MIX Fold while the NEX Slide and NEX Roll should have extendable displays, the report said, citing MyFixGuide.
It is also worth noting that all of these devices are under the NEX line of Vivo phones which is no surprise considering the NEX line doubles as Vivo's experimental line of smartphones much like Xiaomi's MIX series.
Earlier, a report said that Vivo has patented a new foldable smartphone design with a stylus.
Vivo Mobile Communication filed a design patent with the WIPO (World Intellectual Property Office) in February 2020. Titled 'Display panel and mobile terminal', this patent got approved and published recently.
As per the documentation, the smartphone will feature an inward folding screen that unfolds into a tablet, the report said earlier.