I want to be able to turn access to a particular external 2.5" Hard Drive ON and OFF as needed. So, several years ago, I invested in a 4-port powered switched USB hub from Ebay - which worked well for some time, and when that stopped (one socket at a time) I bought another - two this time; and each of those worked for a while, and then stopped. I am now at my 4th supply and that phenomenon persists. Currently, when the hub fails, I remove the ext HDD USB lead and then put it back, and the drive is seen again. How long that will last is anybody's guess. With the latest iteration, it took ONE month of use before it failed. I would like a permanent remedy - or short of that, a reasonable explanation for the apparently predictable failures. I must admit, the model that I have been getting from Ebay - whose products are usually good - I have not found in any Google search. Can anyone help ?