Hi,
I own a Chieftec SNT-3141 which is a small four hard drive rack.
You have to install your hard drives on a slider which then will go into the rack. The slider will be locked in place by a huge plastic lever. It also has a small radial switch on it which will lock the lever in place so you do not accidentally open the wrong drive bay. As I am very happy with the big lever I am not using this small switch at all but guess what? That stupid thing still breaks even if you are not using it! And it happened not only once but twice now (out of four I own). Here are the pics:
One of the damaged sliders: 
Close up of the damage on the slider: 
My first broken radial switch 
The first and second radial switch next to each other 
This damage will leave you with a functional lever but you will not be able to lock it anymore. And from a slider which costs a freaking 17€ if you buy a replacement, I expect more, not that it breaks like this multiple times!
So if someone has some advice which hard drive racks I should by once I have to replace this one, please send me an email. I prefer ones which have the hard drive screwed to the slider instead of just applying pressure or similar mechanisms. Also, it should be either be an 4 or 5 bay rack.