egevaThe Description is pretty clear. At the very least you have a 50% chance of getting the base model RX18Ps and less chance of getting the better quality models down the list.
As time has gone along, and more people have joined, your odds of getting something better have slightly improved as additional models have been “unlocked” (See lower in the description).
MEE Audio RX18P, randomly selected from black or blue ($9.99 value): 50%
MEE Audio Crystal, randomly selected from blue or silver ($39.99 value): 23%
MEE Audio M6 2018 version, randomly selected from clear or black ($19.99 value): 25%