Both my Syrian and dwarf hamsters have the 10cm diameter tunnel. It's lightweight, chewable (my Syrian has only made slight inroads into it!), aesthetically pleasing and excellent value for money. Will order again if the Syrian destroys the first one!
I have regularly purchased willow tunnels from zooplus for my guinea pigs, they are exactly as described and will continue to but these good value tunnels from zooplus, I usuallu purchase them when they are on offer to save on costs and also order over £19 worth to save on postage costs