PH-100L is with U-174/U Plug "listen-only" Helicopter headset. Provides the same comfort features and adjustable headband design as our standard noise-attenuating models. Listen Only Headset Comfort soft Foam Head Pad Over-the-head Adjustable Stainless Steel Band,Adjust it to your needs Comfortable half gel half foam ear pad Volume control Switch Passive NRR 23dB coil cord terminated U-174/U Helicopter plug