Great set! What you have here is a NOS KLH Headliner III Car Speaker System (likely late 1970s–early 1980s), complete with:

• Two flat high-frequency speakers (meant to mount above doors, windshield, or headliner)

• Control box with balance controls (left/right)

• Wiring harness and connectors

• Mounting hardware (brackets, screws, caps)

• Original box + instructions 

About KLH & This Model

• KLH was a highly respected American audio company founded in 1957 in Cambridge, MA (same town as Acoustic Research). Their gear was known for high-fidelity, space-saving speaker design.

• The Headliner series was marketed as a way to upgrade in-car stereo systems at a time when factory speakers were low quality. The slim "flat panel" design allowed discreet mounting while still improving treble clarity.

• The balance control box was an advanced feature for the time, letting users adjust speaker bias left vs. right (something not always built into tape players or radios then).