The Black Box Headphone adapter for using 2ch amps to power headphones. 

Bidirectional

5way heavy duty speaker binding posts, for use with banana, bare wire or large spades into either a 4pin connector or 1/4"

This is a lab grade module... all components are heavy duty and expected for a lifetime of use. 

Internal wiring is silver plated OFC copper with Cardis silver solder.