This is the second Wasserstein light I've purchased, and it shows a decline in manufacture--that, or they put a really weak coin battery in it.  I've had it for less than 2 weeks and it's already begun to fade.  I carry a fair number of items in my purse, so, I would expect a purse light with any kind of sensitivity at all to light up immediately.  This one does not.  I will not be purchasing this product again.