There have been efforts to further increase the accuracy of ERCLMDs. One concept was to measure the impedance characteristics using more than two frequencies. In the Endo Analyzer 8005 (Analytic Endodontics, Sybron Dental, Orange, CA, USA) and AFA Apex Finder 7005 (Analytic Endodontics) five different frequencies have been used and the device measures both components (phase and amplitude) of impedance at each frequency.