I need a replacement part for the potentiometer depicted below, dimensions are approx. 16x13.5 mm. The bottom reads "B100K" and "SEL" and the resistance between the two outermost contacts is a little less than 100k, but a quick Google search didn't come up with a definite match (this particular model has a small inside thread to connect to the radio dial). The radio was built around 2012, if it helps.
It's a 100K linear taper pot designed with a mechanical construction to allow use of hardware and knob for radio tuning. Probably made by one of the many potentiometer manufacturers in China. Here is a similar construction one:
I don't think you're going to be able to easily find a replacement unless you live in China (and even there it would not be straightforward).
As @jsotola and Kyle suggest, you can probably fix whatever is wrong with that one by carefully opening it and possibly adding some conductive ink to the ends, and cleaning the element/wiper with appropriate products. Typically the wiper has only a thin plating layer, and the element also is fragile, so be careful not to permanently damage the pot.