Having never used a prostate massager, choosing an Aneros is proving rather difficult.

There's a beginners, intermediate and advanced range to suit, but they all look pretty much identical.

There's no clear difference between the ranges that purport to be catering for prostate massage experience level.

So, what makes each range suitable for each and what should me, as a beginner, be looking for when buying?

Which Aneros should I buy?