Biometric monitoring devices, including various technologies that may be implemented in such devices, are discussed herein. Additionally, techniques, systems, and apparatuses are discussed herein for utilizing two different Bluetooth communications interfaces, one that provides Bluetooth classic (base rate/enhanced data rate) communications functionality and one that provides Bluetooth low-energy communications functionality, in a common device. The techniques, systems, and apparatuses may elect to use a particular Bluetooth interface based on various criteria.