The set has never been used. It comes as shown in photos without retail box or any accessories. The small transmitter is missing the battery cover. Both devices are 9v battery operated (not included)

The Allsun Ultrasonic Leak Detector & Transmitter Finder EM 282-T is a reliable tool designed for detecting various types of leaks in HVAC and refrigeration systems. With a frequency of 40KHz, this detector can effectively find leaks in systems using chlorofluorocarbons (CFC), carbon dioxide gas, and hydrofluorocarbons (HFC). Manufactured in China by All-Sun, this mechanical device provides accurate and efficient detection for maintaining and repairing HVAC and refrigeration systems.