As already mentioned you need to count the number of teeth.
But I've replaced the jockeys on a SunTour Cyclone GT 2 with BBB Rollerboys sealed bearings.
They look the same as the original (ie black) and would also fit VX GT etc.
Here's my thread about it:
https://www.bikeforums.net/classic-v...-bdp-01-a.html
Sealed bearing top, SunTour original bottom
