That's the X950H, the step-up model and successor to the X950G (obvious enough from the name).
X950H is Sony's highest-end 4K LCD of 2020, and comes in 49", 55", 65", 75" and 85" screen sizes. The X900H is a mid-range set and will come in 55", 65", 75" and 85" screen sizes.
There are a few differences, like the X950H featuring X-Wide Angle on 55"-85" models, which improves viewing angles at the expense of native contrast. It also uses the X1 Ultimate processor (currently Sony's best picture processor), has higher peak brightness (in excess of 1,000 nits), etc.
The X900H on the other hand will use a conventional VA panel without X-Wide Angle layer, which means worse picture off-axis but deeper blacks. It has the older (but still very competent) X1 picture processor and lower peak brightness.
For gamers, the X900H has one potential advantage in that it will feature an HDMI 2.1 port and support features like Variable Refresh Rate and Auto Low Latency Mode, in addition to eARC which is already supported on various other Sony TVs (including the X950H).
Last edited by teachsac; 02-20-2020 at 08:27 AM.
Reason: Retail link removed