VERY POOR QUALITY.
You might say, with a price below 1 euro, what do you expect?
You're right, and I agree with you, but...
these ones are like they gathered some sticks from the beach, cut them randomly, inserted a spring in between to hold them (kind of), put them in some leftover plastic wrap (from something else) and sell them as clothespins.
The grooves they have to fit the spring are mismatched (higher or lower), causing them to break under slight pressure when you try to use them.
They are also uneven sticks, which might explain why the spring doesn't fit properly.
I bought them mostly for testing, but they turned out to be rubbish.
Let's move on to something else.