It is expensive for something that doesnt vibrate/move/anything, but it is worth every single penny!
And don't be put off by the fact that it says 'Large' because it is not at all massive (see the item page fort he actual dimensions).
The variation in size between the difference 'sizes' is minor really, but the weigth difference looks to be the main adjustment.
And, with it being so smooth and shiny, its fine to leave in for a while, because even if your lube dries up, you can still slide it out pretty easy 
PS. I dont work for nJoy haha 