That 12-25" may be what I have for a sitting bipod as well. I don't use it much anymore but sorta remember it being a little short, but way too tall for me to use prone with good form.

In comparison, here is the 6-9" model, collapsed at 6". (To be fair, there is a QD adapter and a rail between the handguard and bipod. Directly mounted, this model would be about half way extended to get to that height.)

[Linked Image from i.imgur.com]