Well whaddya know. If you squeeze it, it makes a barely-perceptible click.

That's actually quite a brilliant piece of industrial design, in terms of the cleanliness and sleekness of the product. Shame that the cleanliness completely obfuscated its function. Apple does that kind of thing a lot. The bluetooth headset is almost like that. There's a button on the top edge, but it's so flush with the casing that you can't see it and it's hard to figure out what to press. The new miniature wireless keyboard has a power/reconnect button, but again, it's flush with one end of the keyboard and you can't tell where it is. I swear I turned that thing around ten times looking for the button. The symbol indicating that it's the power button is so artistically tiny that you have to look really hard to see it against the shiny metal casing. And so on.