It's in the description of the picture. Sometimes it helps reading it ;).
I do prefer him with claws on both hands too, relaly. I was just in a mood to do the single claw at the time when I drew this.
Meaning, you would want him to have two robotic arms?
Yo, dude, you've actually managed to pin point all of my favorite versions of The Shredder in one single picture. That's awesome :D