Been looking at the berghaus cyclops light on line but cant find one localy to see, Was wondering what the back is like is there any rigid support or is it like the Arete with a flexible back.

I like the cyclops back system as it is simple, very tough and capable of making a heavy pack a comfortable carry...

I have a number of berghaus packs and they are all very good, including the Arete!

The Berghaus Atlas 100l? that has the cyclops 2 back system -It has two bent aluminium bars that run top to bottom.  there is also a horizontal bar attached to this to stabilise the main bars.  The bars can be removed and bent to increase comfort if you are an odd shape.  They also have tensioners inside the that allow a small degree of tweaking.  Having the extra rigidity makes packing easier, great on multi day trips when you may have to pack up in a hurry.

Good luck