The newest of the CB series is the 6000.  I have had good reports and not so great, not as easy to clean as the 2000 and 3000 for one.
http://www.tickleberry.co.uk/pages/cb6000.html
Being flatter and more comfortable may be a plus for any cock controlled chastity enthusiast.  What’s nice is the bottom opening for public urinals, but part [...]