Tried the StarTech brand, which I found is made much better than the Oxsubor brand. But neither one actually worked in converting my USB keyboard to PS/2. My application was using a PS/2 keyboard with TASCAM audio products. Apparently, TASCAM requires a "real" PS/2 keyboard, which I found works great when I use a PS/2 keyboard. But I have many USB keyboards.
Bottom line is StarTech adapters are manufactured much better than these cheesy Oxsubor brand adapters.