More microphones result in better sound quality and enable the device to filter out background noise.
Parrot Zik Sport: 8
16. has an on-ear form
This device comfortably rests on top of your outer ears. As it doesn't block out everything from the outside world, it's preferred in places like office environments and recommended for outdoor activities.
Beats by Dre Mixr
Street by 50 On-Ear
23% have it
17. has a coiled cord
A coiled cord typically offers more flexibility as it can be extended, and taken outside for example.