You'll find our 500K US pots. US = 9.5mm thread (.375")
First the normal body, then small body. At the end, long shaft (XL) 500A- and 500B- for the SKU.
Also if it is solid or split shaft (SKU have SO or SP)
End, Size of shaft (thread + top). 15mm or 18mm.
Note diameter ALPHA solid shaft are 6mm. CTS solid shaft are 6.35mm diameter (1/4").