This 40 GIG drive is a direct replacement for the 20 GIG that came in my Toshiba Protege 2000 purchased in 2003. Just a shame that it didn't come with an 1.8 in to 2.5 in adapter so that I can use it in my desktop. I've since found the adapter over the Internet for under $20.00 N.B. this is the older 50 pin driver and not the ZIF version.