Regarding Ternence cages... Having just spent a full week locked in one I thought I might offer my comments on the various Ternence cages I've tried. First off, here's a link to them: https://smile.amazon.com/stores/TERNENCE/page/DAF15518-05E0-4946-A51B-03FE9DF14A19?ref_=ast_bln. By the way, if you are not already using SMILE.amazon.com, please do and choose a charity... don't have a favorite charity? Then select Shriners Hospitals for Children.
My favorite cage by far is the Mature Metal JailBird which I've owned for more years than I can remember, and have worn for many months 24/7. Even then, the only reasons I remove it are for doctors, shaving, swimming and skiing. The JailBird cost over $300 and was custom sized. It's the most comfortable cage I've ever worn for long-term use and well worth the cost (imho). I did, however, want to try other cages and the cost & selection of the Ternence were very appealing.
Given all of that, the Ternence B07K13SF32 (https://smile.amazon.com/dp/B07K13SF32/ref=emc_b_5_t?th=1) is the most comfortable cage I've worn, besides the JailBird. Eight days on, very comfortable and little bulge (actually less bulge than most others due to the sideways lock. Smart. The biggest downside to this cage is the hinged ring. Although getting a closed-ring on can be a challenge, holding the hinged ring closed while fitting the cage on while not getting pinched by the pins on the back of the cage while fitting in the sideways lock while trying to remember why I'm doing all of this required more skill and patience than I had expected. My suggestion based on experience: with a little lotion, get the cage on first, then deal with the ring and holding everything together. This cage is a bit narrower than others, which actually feels nice once it's on but makes it more difficult to get on to start with. This cage supports the use of a 4" urethral tube which, I'm happy to say, can be inserted/removed without removing the cage.
The other Ternence cages I tried were the shorter ones... a couple that have been described as "caps" which I don't find comfortable for long-term wear and too easy to pull out of. Someone in here mentioned disappointment at how easy it is to pull out of cages, and that's mostly true. However, remember that we're not the "Man in the Iron Mask" here... this is a game we play with our partners and/or ourselves. Unless you are going to spot-weld something on, you will be able to remove it. That shouldn't take away from the fun in playing with it.
My last comment is to pay attention to the measurements and sizes that Ternence lists. Sometimes they measure length from the back of the pins to the tip while other times it's from the front of the pins. Also, measuring along the top or bottom makes a difference. Basically this is where they fall short: you may have to buy a couple in order to find the size (mostly length) that works for you.
I put back on my JailBird and expect to wear it 80% of the time with the other 20% being the latest Ternence. With and without the tube.
Sorry for being so long... I'll be happy to field any questions and I'll post more pictures to my albums soon.