I now have 2 failed external hard drives that won't mount. They are well past warranty. Opening one reveals two 3.5" HDDs...connected to the controller via SATA. (haven't opened other one so not sure ...
A few years ago I bought a WD My Book Pro 2. It worked fine for a while, then one of the drives failed and I sent it back to be replaced under warranty. I never got around to setting up the new one ...