Tobily is right, it isn't much use if you start using it in established labour.

I used it at home before I went into hospital, and it made a slight difference. I took i off when I got to hospital because I got in the bath. I tried it again after the bath (I was in the bath for hours and hours) and it did nothing.

The pads cost me $25 for 4. I hired mine for $10/week plus a $50 deposit. It is so cheap that it is worth a go.