Alternator adjuster - anyone tried these?

[KKson]

GV said:

Without sounding as though I am being a numpty....what is the benefit of a rose jointed adjuster?

It's just way easier to tighten it a little on the opposite thread adjuster bar, rather than trying to pull the alternator against the belt tension, hold a spanner on one side of the nut and a socket wrench on the bolt head, whilst trying to feel for the 1/2" of belt movement.