Wearable biometric monitoring devices, interchangeable accessories and integrated fastenings to permit wear

A device comprising:

• a biometric monitoring device having an outer housing, the biometric monitoring device having:
• a housing,
• one or more processors,
• one or more biometric sensors, and
• a memory, wherein:
• the one or more processors, the one or more biometric sensors, and the memory are communicatively linked,
• the memory stores computer-executable instructions for controlling the one or more processors to obtain biometric data from the one or more biometric sensors, and
• the one or more processors, the one or more biometric sensors, and the memory are contained within the housing;
• and
• a viscoelastic wrist band having an opening sized to allow the housing to be removably inserted into the wrist band and worn on a person's wrist.