Sony's 7cm unit Equivalent to FF70EG by FOSTEX It's small, but depending on ingenuity, the sound quality is surprisingly high (Yoichi Murakoshi)
Maintenance information: 2022.6.12 Sound output confirmed
Accessories: mounting screws, FF70EG spec sheet, box
Main specifications: 8Ω playback frequency characteristics 135Hz to 20kHz 83.5dB baffle opening φ61mm+scale 320g