Those Tunze Nanostream pumps need to come with a warning about the strength of those magnets. I got one the other day (because they are, in fact, awesome circulation pumps), and for the second time in my life, I underestimated the strength of the magnet, tried to pull them apart, lost my grip, thumb slipped and WHAM! I can't believe how much pain there was. And I've experienced childbirth, and a torsed ovary, so I'm no whimp... but damn that hurt!