For serious chastity players, nothing beats a neosteel.
http://www.neosteel.de/Nsepmain.htm
Probably the best made for long-term chastity. I corresponded with a gent who had been locked up in a neosteel for 8 years before replacing it with a new one. Prostate milking once a month but other than that no sexual stimulation. That was 3 years ago, for all I know he is starting his second decade of chastity.
I enjoy chastity play, but real long term chastity? Much better as a fantasy.
For those concerned about hygiene, a Birdlocked would probably be your best choice (and much less expensive, to boot!)
http://www.birdlocked.com/
I personally split a CB-3000 and a Curve due to nocturnal erections, and my CB-6000 while better designed is showing signs of strain even though I use it maybe 3-5 days out of the year. (It's 3 years old now)
As for how long the denial is in a provider situation? It is up to you. You could put it on before you get there, whether a week or in a gas station bathroom on the way to the meeting. Some teasing, denial, and at the end you get released in more ways then one.
Or, you can show up, have her put it on, commence with the teasing, perhaps some implications that it might be on for a long time, maybe she "loses" the key, followed by finding it and giving you a release. Or maybe she hands you the key on the way out. Or she mails it to you the next day. Or you come back for another visit in anywhere from 5 minutes to overnight, a week, maybe more if you dare, and she unlocks you then.
If you are good enough.
Enjoy!
