Tango® TX1 Single gas NO2 detector with revolutionary DualSense® Technology, includes two of the same type sensor. DualSense® Technology increases worker safety, regardless of bump test frequency, while reducing overall costs. The Tango has a two-year battery life and a Guaranteed for Life warranty. Guaranteed for Life does not include battery, sensors and filters. The CO and H2S sensors are warranted for 3 years from the initial purchase date. All other sensors are warranted for 2 years from the initial purchase date. DUE TO THE SHELF LIFE OF GAS SENSORS, MOST MULTI GAS MONITORS ARE MADE TO ORDER BY THE MANUFACTURER. PLEASE ALLOW EXTRA TIME FOR DELIVERY OF THIS PRODUCT.