How can I say the sex of them?

[Varmo]

Hey.. I've got two opaline red rumped parrots. But how can I say are they males or females?

 

[MayMaroa]

Hi welcome, Well you can get them DNA sexed

 

[Rozalka]

Hi welcome, Well you can get them DNA sexed

It's unnecessary for red rumped parrots.

Unfortunately I am not an expert on this species. Males are more colorful. Do you know how old are they? Young ones are similar, so if they are too young, you need to wait to tell their gender.
(Here I wanted to upload a picture of a male but I failed)

Try to Google how opaline male and female look like and how old they need to be to say the gender. For me the left one looks more like a male and the second like a female but I don't remember how exactly female should look like