This PCB adapts a 9mm pot with a 6.35mm shaft to a PRV6 footprint.

It can be used with the 212, 258, 291, 296, etc.

The 212 would use 1 adapter, the 258 would use 4 adapters, the 291 would use 2 adapters and the 296 would use 5 adapters.

Note: the product for sale is the small PCB only, the potentiometer is not included.