Plug them into the One just like you do for music players, smartphones, or tablets. We have carefully specified the pair you receive with your stethoscope, but you can use any pair that you have or purchase that connect to a standard 3.5mm headphone jack. You can even use headphones that have a microphone, such as those you use on a cell phone. Yes, we thought of everything! Just keep in mind the advice we give about which headphones work best.