You may need to wet the chamois pocket and site you are measuring to improve the impedance. If you are not getting good impedance, (under 5), use a Q tip soaked in ElectroMist to carefully wet the chamois pocket and the site you are measuring, until you get a lower impedance reading (suggested by Larry and Paul at Discovery Learning Associates). Take care not to get the hair or the band wet between testing sites to avoid salt-bridging, as per the recommendation of Tom Collura at BrainMaster Technologies.