Review on Nimitz 2nd HDD SSD Hard Drive Caddy - Compatible with Lenovo Thinkpad T400 T400s T410 T410s T420s T430s T500 W500 by William Lopez

99.99% perfect fit (the edge closest to the laptop's USB port sticks out maybe a third of a millimeter, but that's just because I'm very picky and try to make something to find that will show the buyers). It was very easy to replace, very easy to install my external hard drive in, so it's now an internal hard drive (wow! Less stuff to carry around!) and runs very smoothly. I use it to store and access all my photos that I use for Lightroom, so the faster transfer speed (compared to USB 2.0 since my hard drive is external to my computer) is a nice improvement.