Well, firstly, the Liitokala Lii-100 can charge both Li-Ion and NiMH chemistries, so it shouldn’t be a problem.

Second, I’ve seen these cells before, and they charge at regular li-ion charge voltages.

So a 4,2V lithium-ion charger will work well.

If it wasn’t for the 3rd contact I did not notice.

On a second thought, don’t let the customer buy these.