Acoustic indicators - clear audible warnings that tell you when the device is turned on and off, the battery level is low, paired, connecting, disconnecting and reconnecting. Broad compatibility - compatible with most Bluetooth enabled devices, such as mobile phones, tablets, iPhone watch, PC and GPS navigation. Safe and comfortable fit - the earplug is ergonomically designed and optimally adapts to the shape of the ear canal, making it comfortable to wear and will not fall out. Private and unobtrusive - small enough to hide in the ear or under the hair, weighing only 3.7g, the earplug will go unnoticed. Ideal for listening to audio - enjoy audio books or podcasts on the go and follow GPS instructions while driving. Compatible with navigation systems capable of Bluetooth transmission (such as the Garmin Zumo series). Please note that some navigation systems do not have this function, and therefore can only act as a Bluetooth receiver.