This http://www.ifixit.com/Apple-Parts/Unibody-Laptop-Dual-Drive/IF107-080
The SuperDrive in the early 2011 MacbookPro 17" is 9.5mm. Unless I am blind, the website does not list any measurement for the caddy, but looking at the picture of the caddy with a hard drive in it, it would seem that the caddy is thicker than the 9.5mm hard drive placed in it. The website lists the caddy as being compatible with an early 2011 MacbookPro 17", but I'm not too confident that it actually is.
The SuperDrive in the early 2011 MacbookPro 17" is 9.5mm. Unless I am blind, the website does not list any measurement for the caddy, but looking at the picture of the caddy with a hard drive in it, it would seem that the caddy is thicker than the 9.5mm hard drive placed in it. The website lists the caddy as being compatible with an early 2011 MacbookPro 17", but I'm not too confident that it actually is.