I've been wearing the HTV4 nub for 2.5 years without a break. So yes, you can wear it indefinitely. It's also very comfortable. You forget there was a cock attached to you after a while. This seems to be very similar to the Nub.
Have retoned the model shown only 2 days ago. The rings are great, the cage and the locking mechanism not so. Nevertheless, the ring design is perfect and I hope that soon you can buy the ring with a different closure system, which does not squeeze the foreskin and reasonable lock cylinder.