Omnitrix

Azmuth mentioned a Third Omnitrix in Map of Infinity (episode). He was planning on giving it to Ben, but it wasn't complete yet. The second reason was because Ben's maturity needed to increase before he could do so unless there is a situation that requires the risk of Ben giving his new Omnitrix but only if it's complete enough.

In The Ultimate Enemy: Part 2, Azmuth gives it to Ben.