The Buttinski D361 Test Set offers the latest in data protection. Test the POTS service on alive ADSL line without fear of bringing down the data service. With this innovative design, Tempo continues on the cutting edge of butt-in test set technology. High-voltage alarm and a quick release, non-metallic belt clip composed of Verton® RF, a strong, lightweight structural composite. This combination of rugged technology enables Tempo to offer the best industry warranty period of 3 years.