"Before beginning my review, I'd like to thank both Carlos and Sandra for their help with my order. They both bent over backward to accommodate my specific needs, which were not easy. As far as the product, absolutely phenomenal!!! When I received the product (in Guatemala) it felt a big deal, even more so than buying a new cell phone and unboxing it to see the shiny new product. Receiving my CTM IEM's was much more exciting than that because it is custom made just for me. The presentation was fantastic, the box and everything in it was very well presented. This truly felt like a white-glove service and a very high-end product. I was very careful while opening and handling my new IEM's but ready to hear music with them, try out the fit, and experience the sound isolation. All three points get a 10/10. I listened to everything from the news to podcasts to metal music, super clear sound and great balance in highs mids and lows. The fit was tight, which is what I expected, and will take some getting used to. The sound isolation is surprising! My wife was speaking to me after I put them on, I couldn't hear her lol. I jammed on my drum set with these on and it is exactly what I was hoping for high-level ear protection and clear sound while practicing to music. Carlos suggested the CT-400 and I now understand why. Great product, exceptional service, and memorable experience. Thank you CTM!"