Revomaze Obsessions are available in Blue, Green and Black flavours. They’re machined in tough plastic to similar tolerances as their Extreme cousins, but they’re significantly cheaper (and lighter). For me, the only downside is that when they’re opened, the core is never fully exposed, so you can’t ever see the actual maze cut into the core, which is a pity.[The pic shows one fully open.]
When they were first launched, a couple of different coloured sleeves were available, with the colour of the maze core being represented by the colour of the ‘R’ logo on the end of each core…these days all of the cores (in this style) are black – so pay attention to the colour of the sticker or you won’t know which maze you’re working on.
Some people prefer the Obsessions over the Extremes – I suspect that it’s a matter of taste. They do feel different when navigating through the mazes, but the mechanics of the solution are pretty much identical between them. They are a lot less intimidating to folks trying them out for the first time, and I guess that folks are far more likely to take a punt on a £20 puzzle that they don’t know than they are on a £85(+) puzzle they’ve never played with before. [I also find it a lot easier to part with an Obsession for months on end to let a mate have a bash at solving them than I would parting with one of my Extremes!]
Commercially it makes a lot of sense to have the cheaper versions available – and having Extremes available for more serious puzzlers (or hoarders like myself) covers both ends of the market.