When listening to sound sources produced by ASMR or binaural recordings using traditional headphones or headphones, a unique discomfort occurs in the high frequency range. The final version of "E500" was created, allowing you to feel the timbre, spatial image and directionality of sound the creator intended. Today, "E500" is widely used by ASMR enthusiasts as a standard ASMR headset. It can intuitively hear not only the performer's voice and breathing, but also the distance from the microphone and the direction of the speaker, so it has become popular as a "sexy headset" centered on SNS. They are now also being used as monitoring headphones for sound checking on ASMR content and 3D game production sets.

The smallest and lightest product in the COTSUBU for ASMR MK2 series, the deep-fitting design achieves high sound insulation. The lightweight and comfortable design weighs 3.5 grams per side so you'll forget you're wearing one. Since it fits perfectly in any ear, the earphones won't pop out of your ears easily, nor will they come into contact with the earphones and cause them to fall out when putting on or taking off the mask. In addition, the "deep fit design" allows the earphones to fit firmly in the ears despite their small size, achieving high sound isolation even without active noise reduction.

The guidance voice is provided by Junko Kubo, a freelance announcer active in Japan and abroad. Freelance announcer Junko Kubo is in charge of audio guidance such as "power on" and "Bluetooth connection". Junko Kubo is responsible for the audio direction of the final/AG products starting with the ZE8000MK2.