Count me in as another impressed user! ***UPDATE [Battery Life]: I received the trackball on 14 October and it just now died on me, on 7 November, 24 days later, using only the charge that came out of the box. Run a bit wide. I hadnt tried on a Birkenstock in decades and didnt remember the arch is a bit high so I was so sadly unable to keep them. -The rubberized tread on the bottom keeps me from slipping on slippery floors, perfect traction. I ordered these due to all the good reviews. It was pure luck that I checked my reviews today. As I took them off while the music was playing, the music stopped when I took them off my head and started again when he put them on. I regularly play for 2 to 3 hours when playing online with friends. Compatible con el uso de auriculares inalámbricos.