I use a DT Systems H2O 1820 and keep it on 8 or 9 (out of 16 levels) and she knows she needs to behave when she has the collar on. She's very high spirited and a real sweetheart. So nobody gets the wrong idea - I'm talking about my setter...

Remember NEVER to use it as a punishment, only as a training aid when she disobeys a known command.