Wheel nuts issue

It seems that my honda fit has one wheel nut different than others in each tyre. I cannot see all of them as they have cover need to be opened but I am worry that if I open it it breaks! Anyway I remember once I went to tyre station two years ago and they told me why one of the nuts different and needs special lug wrench. Is this general for all honda fits and is it locking nuts? If so, are all the tyres have them? Can I go to tyre station to change all nuts to standard one? Or better to buy specific tool and keep those nuts?