Riddle # 348 (Solved By hina)

[naz]

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I'm double, I'm single,
I'm black, blue,brown,green and gray,
I'm read from both ends,
And the same either way.
What am I?

[hina]

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I'm double, I'm single,
I'm black, blue,brown,green and gray,
I'm read from both ends,
And the same either way.
What am I?

Eye

[naz]