Yup is 15.4mm driver + plastic cover = > 16mm. But the main problem is not the diameter of the driver but the shell shape which is characteristic for all TONEKING buds.
I have a fit issue with MX500 (15.4mm drivers). The only shell for this type of driver which fits nicely in my ear is
DP100 type and some metal shells with "concave arc" shape.
See this
post where I explained what the problem was with different shapes. Even 14.8mm driver with "convex arc" shape like Nicehck EBX can cause a fit issue