I gave this product a fair shot. I put down my 'traditional' crimping curler in leiu of something a bit fancier (and less pinchy!). It says to use after applying mascara, which I didn't understand, so I tried it both ways.
The device requires one AAA battery (not included). You switch it on and a tiny pink indicator turns white when it is hot enough to curl your lashes. You then sweep the curler upwards from lash root to tip several times to get a nice curl.
What can I say? I did NOT notice a curl in my lashes what-so-ever. That's the long and short of it.
The best way I've found for curling my lashes is putting my hair dryer on its lowest setting and warming up my metal lash curler just a tiny tiny bit and then using it to curl lashes and then applying my mascara immediately afterwards. It's quick, easy, cheap (no extra tools required!), and the curl it produces lasts all day!