These are my beloved Sennheiser HD239s. They are a portable on-ear open headphone and are some of the most underrated gems. The renown and well-respected Tyll from Innerfidelity has these on his Wall of Fame and I couldn't agree more with his claim on these being the "perfect office headphone". They are light to take on and off repeatedly. The combination of an on-ear and open design allows you to be aware of your surroundings. They are compact enough to store away in my drawer. Importantly, they sound superb! They do leak sound but I find them loud enough at 70% volume making the music nearly inaudible for those a metre away. I am yet to receive a complaint/comment from others. Over the years I have had the pleasure of owning a wide spectrum of audiophile gear (Stax being the pinnacle), yet I keep coming back to these headphones as my go to for both office and transit use (I walk 20mins to work each day). In a nutshell, I would say they are a refined Koss PortaPro with upgraded comfort for those wearing thick-frame glasses. We are approaching our five year anniversary and I will be looking to replace those worn-and-torn earpads. Let's make it ten!