The latest Trident Z Neo memory kits come in 16GB (2x 8GB) and 32GB (4 x8GB) capacities. Both kits respect JEDEC's DDR4-2133 baseline out of the box. However, they are binned to run at 3,800 MHz with impressive CL14-16-16-36 timings. As you might be able to deduce by the memory speed and CL timings, these Trident Z Neo use Samsung B-die chips.
G.Skill didn't specify the operating voltage for the Trident Z Neo DDR4-3800 kits in today's announcements, and the corresponding products pages were not yet live at the time of writing. However, the provided screenshots point to 1.5V.
As with any G.Skill memory product, the Trident Z Neo memory kits support the XMP 2.0 (Extreme Memory Profile) standard and are backed by a limited lifetime warranty.