Sonix Imp 100 digital loudspeaker impendence meter
http://www.coopermedc.com/sites/coopermedc.com/files/products/datasheets/cooper-medc-datasheet-dsso0101issa-imp-100_0.pdf
http://www.coopermedc.com/sites/coopermedc.com/files/products/datasheets/cooper-medc-datasheet-dsso0101issa-imp-100_0.pdf