First, welcome to the forum!
Next, chastity devices.
You could probably split chastity devices into three categories.
1- used during a "play" scene, perhaps for an hour or two. Provides frustration, stimulation, pain, an opportunity for a bit of humiliation
2 - OK to be worn for a day or so, more of the above effect
3 - OK to be worn for long periods, eg weeks, months, years! usually part of a Domme/sub relationship, providing clear evidence of who is in charge.
Pretty much anything will work for the first. The "gates of hell" are a plaything, not a chastity device, and like all devices, need to fit to do any good (or bad
) If the rings are a larger diameter than your erect penis, it's a waste of time and money, the whole point is to make an erection uncomfortable. The same applies to cages with spikes inside, unsuitable for anything more than a play scene. Incidentally you can have a lot of fun the some thin cord, binding the balls and shaft, adding weights, tying them to something fixed or other body parts.
For the second use, either of the two devices you've found should do the job, but again, size matters. In my experience, as a "grower", these devices and similar ones rely on the gap between the base ring and the cage ring to hold it in place, with an erect shaft to reinforce this. For me, with a "flaccid:erect" ratio of about 1:3 if there is no stimulation and the shaft goes limp, the device drops off at some stage. You might get lucky, or if you are a "shower" and maintain the length and diameter.
In the third case, get a custom device made to measure, from good-quality stainless steel - I have a MatureMetals "JailBird" - you MAY be lucky and get a close fit "off-the-shelf" but you will probably spend as much trying different types as you would getting a custom device that fits. I would stress that the fit means snugly enclosing the flaccid shaft in both length and diameter. Get that wrong and you will suffer, and not in a nice way.
There will no doubt be people who will say they have no problems wearing a cheap device for long-term, but that is likely to be that they just got lucky with sizing. £40 is at the cheaper end of the spectrum, the usually Chinese manufacturers have a flexible approach to specifications, and "stainless steel" may turn out to be nickel plated cheap casting metal, low grade stainless steel or chromed ordinary steel. For short-term wear this is not much of a problem as long as you inspect the device regularly for flaking or corrosion. You get what you pay for.
