How does this code find if a string is palindrome

So one of my friend said this code will find whether a string is palindrome or not
This code works but I am not sure about how this works
pls explain me how this code works
here is the code:

Var = 'radar'

if Var == Var[::-1]:
   print("palindrome")
else:
   print("not palindrome")

>Solution :

Print the 2 Var:

>>> Var
'radar'

>>> Var[::-1]
'radar'

There is no difference but now try with Var = 'hello':

>>> Var
'hello'

>>> Var[::-1]
'olleh'

The second form Var[::-1] reverse the list.