This unit runs in auto or manual mode. This is a brand new unit with a warranty. Many of our customers have been asking for this EKG machine, it is a small, portable, handheld EKG machine at low cost. This unit prints 3 or 6 second QRS segments. This unit can also run in manual mode. This unit is a special North American model, with USA coded patient cable and alligator clips. Included is software and a PC USB Cable so ECG recordings can be uploaded and filed on a computer. Do not confuse this model with lower cost Asian model units. This unit comes complete with cables, battery pack, power supply recording paper, PC USB cable, software and operating manual. Plus also included is a 80 page Insurance Examiners Guide, this is a $39. value. Free Catalog Included! Filter: AC 50/60Hz Lead selection: Automatic and Manual Operation mode: Battery or AC Weight: Less than 1 pound Recording system: Thermal-array printing Chart Paper: Low cost roll type