For the other two that work ... they are very fragile I think it must be handled gently
Otherwise they seem to indicate the correct temperature by against humidity for difficult to say, I have only one hygrometer (except those two) and the values are not the same ... but I can not say which are right or wrong (what bothers me enough)
Still, given the price, I think that we should not ask them too. I do not regret my purchase, but I'm going in search of others to replace those who were broken on arrival