I just got the email this morning (and yes, I actually read most of the terms before agreeing).
It is indefinite whether you get to keep it. The terms say that it remains their property and they can ask you for it back at any time.
It says that IF they want you to return it, then you will ship it back to them and they will reimburse you some/all of the shipping costs. They left it open whether they may want them back.