Large jamming pods on J-16D, three pods are visible but I wouldn't be surprised if there is another one under the aircraft's left wing as well.
Very much looking the profile of a contemporary tactical jammer.
I'm unsure if these pods are in service with the PLA, as in past airshows we have seen in service PLA aircraft shown with export intended payloads -- but at the same time, J-16D is such a unique aircraft that I'd be surprised that they'd stick pods onto J-16D willy nilly.
As for the pods themselves -- the two pods under the intakes look like they are of the same type. We can see a reasonably sized ram air intake on their ventral side, and a bulbous nose/tip radome is visible as well. I wouldn't be surprised if the tail end of those pods also have a radome.
The pod we can see under the wing appears to be slightly smaller, and from the angle I cannot see a ventral ram air intake but I think that is because the front nose/tip radome is so large and protrudes ventrally slightly, blocking the likely ventral air intake from sight.
Both of these pod designs seem different from the ECM pods we've seen equipped on JH-7/A in the past, on J-11B, and on H-6KG/J.
Given the large protruding radomes, I suspect that is the position of the primary antennae, and I wouldn't be surprised if another antennae was present on the rear side of the pod as well.
That would not be dissimilar to how the KG-600/800 series pods seems to have their arrays arranged, and would of course be similar to the NGJ pod as well.
Given the technologies that are mature, I somewhat expect these pods to have AESA antennae, but that can't be taken for granted.
If there are indeed four pods (and by all logic that would prove to be a sensible and symmetric loadout), the pods are likely to cover different bands. Compared to EA-18G, which at present carries three ALQ-99 pods for most missions, or in the future will carry three NGJ pods covering different bands with potentially two smaller NGJ pods (for a total of five), a four pod system of reasonably sized pods for a standard EW loadout is an interesting choice.
Each individual pod is likely to be slightly less powerful than a larger pod (like the current midband NGJ in flight tests), but offers greater flexibility.
Of course, we also cannot rule out the possibility that additional EW pods can be added over time as well.
The loadout so far in the picture is not equipped with any weapons that we can see either, whether it be AAMs or ARMs.
In any case, so far at Zhuhai I'd say the official revelation of J-16D in such a high quality manner is probably the biggest surprise so far, and even more so if they are showing these new EW pods intended to be in service with the aircraft.