From BOSE, their Quiet Comfort Headphones Airline Adapter. This adapter is black.

Features:
- Compatible with Bose QuietComfort QC2 QC3 QC15 QC20 QC20i AE2 AE2W headphones
- Also compatible with all devices with standard dual or single output 3.5mm audio headphone jack plugs
- Designed for use on in flight airline entertainment systems to reduce background noise
- Enjoy powerful balanced sound for music or movies during any airplane travel
Model Number: UAXNMGX1