Package includes TI-1b Transformer Interface.

TRUE RIBBON CA-1A. THE WORLD'S FIRST CIRCUM-AURAL RIBBON HEADPHONE MONITOR!

Both packages include a one year manufacturer warranty. Headphone only package ships with just CA-1a Circumaural headphone, no cables or interface box included, Standard Package ships with the CA-1a Circumaural Ribbon Headphone and complete TI-1b package which includes:

OB Compensation barrel for Balanced XLR & Single-Ended RCA amplifier inputs
HPL Cable for connecting TI-1b to conventional 4-pin XLR headphone level amp output
SC2 Cable for connecting True-Ribbon headphones to TI-1b interface