The Ultimatrix is a device used by Ben in Ben 10: Ultimate Alien. 
Appearance[]
A gaulent watch-like type device
Backstory[]
Originally created by Azmuth, the Ultimatrix's power core was unstable and incomplete so he put the device in high security storage. Albedo stole the Ultimatrix and was able to stabilize the core. Unfortunately for him, Ben's DNA was still the default for the Omnitrix and was still linked to the same database, so Albedo only had access to Ben's current aliens, which excluded Grey Matter. Allying himself with Vilgax, he agreed to help him so he could turn himself back to normal, while Vilgax could have the Earth. After Negative Ultimate Humungousaur easily defeated Ben as Humungousaur, Vilgax threatened Gwen and Kevin's lives in order to force Humungousaur to give up the Omnitrix. Afterwards, Vilgax betrayed Negative Ultimate Humungousaur by using the Omnitrix to defeat him by turning his army of bioids into thousands of Humungousaurs. Later, Ben activated the Omnitrix's self-destruct mechanism to remove it but Vilgax refused, thinking he was bluffing and later suffering the consequences. Ben released Albedo and forced him to give him the Ultimatrix via the same method. Ultimate Swampfire battled Vilgax and Jetray managed to escape.
Ben 10: Matrix Universe[]
It reappears in Matrix Universe but with a new look. It now looks like the AF Omnitrix but light green.