Jawbone UP Activity Tracker (2 Colors)

And how would I know what size to order???

Purchased last week at staples.com for 24.90

Per “some other site:”

S = 5.5 - 6.0 in.
M = 6.0 - 7.0 in.
L = 7.0 - 8.0 in.

So I would order a large. Because I have such a supple wri-ist.