Like the small slits on sides where leather connects for flexibility. Me parece una pasada como se conectan y desconectan estos Sennheiser, ya que sólo tienes que ponerlos de forma horizontal para apagarlos y en vertical para encenderlos. I originally used a cheap lapel mic, to test the setup and it worked perfectly, but was inconvenient. Ribs werent sore while breathing which is a plus considering most belts I buy hit me where my ribs are. Me agradó porque es muy veraniego, pero si quieren un tono más pastel no es la opción. I should have ordered a smaller size but I can live with these. Battery life is quite impressive, standard micro usb changing connection. Large stemmed bases of wine glasses don?t fit in all of the slots, only in the first one. Charged the case and the earbuds until case light turned blue. Lightening fast charging.