Pick your range and you will receive 5 assorted jets from that range.
For example, if you choose 100s you would receive 100, 102, 104, 106, and 108. Or you might receive 100, 103, 105, 106, and 109. So numbers may vary just a little but you'll still get a good range.
If you want a specific jet, you should purchase an individual specific jet. These packs are to help you tune in your bike.
These are commonly found in PHBG and SHA series.
Most Italian mopeds use these, some Tomos, and Derbi to name a few.
No returns on jets. Sorry.