Just in case anyone is thinking of ordering a caddy. I ordered a 12.7 caddy to replace the optical drive, however it is too large to fit. Upon comparing the drive to the caddy it is clearly not the right size. So I believe Marshall made a mistake when he stated that the caddy will be 12.7. I believe it is a 9, not a 12.7.

*Edit* The caddy fits perfectly into my Y580.