For the price these are excellent value for money.
I have used mine in the centre of the bars like a stumpy tri bar, rather than as bar ends, but they function well as both.
Very easy to fit with standard allen key.
I have given them extensive usage since purchase, and there has been no movement.
I personally found that they were more comfortable if some bar tape was also wrapped round them, but I have always done that with all my bar ends.
For the price, difficult to beat.