use conditional in bash script to check string argument

I am trying to write my shell script thing.sh so that upon making it an executable and running it with the single letter ``A" like so:

$ ./thing.sh A

I get the output

A 

If argument 1 is not A, I want the output

Not A 

Here is my code so far :

#!/bin/bash

if [ "$1" -eq "A"]
then echo "A"
else echo "Not A"
fi 

which returns, no matter what I enter,

./thing.sh: line 3: [:missing `]'
Not A

I am trying what I hoped would check something with one or several letters and compare it against the letter A; could someone tell me what I am missing to get this to work? Thank you