The Actiwave Cardio by CamNTech is a waterproof ultra-miniature single-channel ECG waveform recorder. It consists of two electrodes connected by a short lead that simply clips onto two standard ECG pads worn on the chest. It also contains a tri-axial accelerometer, the signal from which allows the user to determine resting body position. For a single-channel 24-hour Holter recording, the Actiwave Cardio gives excellent wearability. The small size (1.5 in. by 0.4 in.) allows for continuous monitoring in a wide range of patients and applications. Key features include the ability to record a full single channel ECG waveform for up to 31 hours, simultaneously recording three axes of acceleration, combining heart rate and activity to calculate energy expenditure, and non-volatile memory.