The Telex Air3100L is a headphone only and does not have a microphone. They both have a noise reduction rating of 21 dB, and are suitable for use in moderately noisy aircraft. All models feature a unique headband design that distributes ear cushion pressure evenly over the entire ear with no pressure points, unlike conventional designs which apply more pressure on the bottom of the ear than on the top. An added advantage of this design is that the headset folds into an extremely compact shape for storage. The Air3100 headset is approved for aircraft use under FAA TSO’s C57a and C58a. The Air3100L headphone is approved for aircraft use under FAA TSO’s C57a.