My steering wheel is 38cm, I got the size 37-39 to be sure! It was a bit difficult to install, but it fits perfectly and seems to be good, I inaugurated it yesterday so I haven't had the chance to see it in use to have a further opinion.

It went in easily and fits quite tightly, it is pleasant to the touch, but as I was putting it on, the thread that ties the leather to the inner rim of the cover broke in three places. For now, the leather is still in place, but I don't know how long it will hold.

My steering wheel is 38cm. Initially, when I tried it, I thought it was small. It takes a little effort to soften it and then it fits easily. I bought it for 5.95€ and it's a good purchase. It feels good and fits properly, without changing position. It's still the first day, I'll see how it will be after some time.
Update: After 22 days, it's stable as it should be.
Update: 11-02-2022 It's the same as when I bought it. It hasn't suffered any damage. It doesn't change position when I turn the steering wheel.
Update 27-10-2022 Almost 1 year and it's still in pretty good condition.
Update 17-11-2023 After almost 2 years, it hasn't suffered any damage and it's stable. The seams are like new.

It didn't fit on my steering wheel, so I simply cut it and attached it with black tape on the steering wheel. As you can imagine, it doesn't fit well and keeps coming off the tape. If you have a small steering wheel and it fits properly, I consider it okay for its price.