Biometric ATMs are self-service cash machines that use a biometric measure to identify customers and allow them to withdraw cash. The biometric check may be the only customer identifier used, or it may be used in conjunction with another format, such as a payment card, a mobile device or an additional security credential, such as a PIN. The biometric measures used will generally include palm or finger vein print biometrics, although they may also include other functionalities such as iris recognition.