Very new terms heard of lately: MedGem, BodyGem, MedGem mouthpieces.
MedGem is actually a device capable of quickly measuring the accurate resting metabolic rate [RMR] of a person, along with oxygen consumption [termed VO2]. Wonder that MedGem calculates a person's metabolism in just a few minutes, determining the person's body's internal efficiency helping the person's consultant understand her/his nutritional treatment requirements for weight loss, weight gain, fitness management, etc.
BodyGem is a MedGem device created by HealtheTech that measures RMR and the number of calories a person's body burns each day at rest. BodyGem assists understand one's unique metabolism and monitor changes, giving ultimate control in managing nutrition, weight and fitness in general.
The mouthpieces are literally filters in mouthpiece format that make it easy for a person to maintain a tight seal while allowing her/him to relax and swallow easily while during the measurement.