The Ultimate Airline Kit - Contains 3 items -Inline Volume Control, Airline Adaptor & 3.5-6.5mm Adaptor
Airline adaptor - This durable, dual-prong airline adapter accepts the standard 1/8 inch stereo pin, allowing you to connect your Shure earphones to the in-flight entertainment systems on most international flights. The airline adapter is included with the SE420, SE530/SE530PTH. Compatible with all Shure Earphones and Headphones.

Volume control - Some playback devices, such as airplane headphone outputs, may be too loud for comfortable listening even at the lowest volume setting. For this reason, Shure offers this level attenuator to reduce the level of incoming signals and allow for precise volume adjustment, minimizing background hiss. Works with all Shure Earphones and Headphones. Included with E4, E5, and E500 Versions.

Adapter - The Shure PA234 is a Female 1/8 inch (3.5 mm) to (6.5 mm) converter for all Shure Earphones and Headphones