Original AKG Titanium Diaphragm Driver Units, 50mm in AKG 701 Sound Style (2pcs) – Earphone DIY Labs
AKG Acoustics Professional studio headphones with 40mm drivers and closed back design ideal for studio recording and monitoring applications. Precisely balanced, 16Hz - 20 kHz response
Archimago's Musings: REVIEW / MEASUREMENTS: AKG K371 (closed-back, over-ear, dynamic driver) - An affordable, modern, standard studio headphone. (And on using the miniDSP [H]EARS rig.)
AKG K371-BT First-class Closed-back Bluetooth Headphones | Sweetwater
AKG N5005 | Reference Class 5-driver configuration in-ear headphones with customizable sound
Amazon.com: AKG N5005 Reference Class 5-driver Configuration In-Ear Headphones with Customizable Sound (US Version), Black - GP-N505HAHHAAA : Electronics
AKG K361 by Harman - Pro Over-Ear Extended Bass Foldable Headphones