CX 300S In Ear Headphone with One-Button Smart Remote - Black

I got response from sennheiser hearing that there is no such serial number in their database

Tengo poco con ellos y no han pasado por la prueba del tiempo, entonces no puedo hablar de esa parte. En cuanto a audio, suenan muy claro, reproducen todos los sonidos con nitidez, le falta un poco de cuerpo/punch al bajo pero siguen reproduciendo correctamente esos sonidos. Se compartan bien en diferentes géneros, a diferencia de otros audífonos que priorizan bajos sobre otros elementos y terminan por ser "especializados" para música electrónica básica, descuidando la experiencia de escuchar otro tipo de música. En cuanto a relación calidad-precio, los compré por la marca, no tengo suficientes comparativas con audífonos de la misma gama para hablar de este factor, pero están bonitos y tienen mejor feel que otros más baratos. Los recomiendo aunque podría haber mejores opciones, sólo que no las conozco.

the sound in the right ear goes fuzzy & static and hurts my ear as it is a piercing sound, i thought it was something i did with crossing wires or fault on my devices, but it happens on every device. after inspecting the wires i can see the wire looks bent/crimped leading up to the right ear bud. when they were packaged the wires were rolled/folded and might have been damaged in this process.

Good stuff

They sound good but are very uncomfortable for sleeping. I use ear buds to sleep to drown out the annoying snoring coming from my husband's side of the bed. I thought I would try out these Senheiser CX 300S ear buds because they were not too much more than the JBL T290 ear buds I was replacing (for the third time in 4 months making them much cheaper if they actually lasted). I paid $16.99 for each pair of the JBL's and the Senheisers were like $35 so it seemed like a good choice. They do seem durable with a metal casing (which is probably why they are uncomfortable for sleeping). They do sound a little richer than the JBL's which would have made them so much better for sleeping. I am keeping them to wear for streaming or to listen to music during the day.