The apex-m15 module features a combination of dual ambient ports (that are larger than the single hole in the m20) and modified internals to achieve -15dB isolation at 350Hz (our standard measurement point) and an additional 4dB cut at 20Hz as compared to the m20, making it the middle ground between bass attenuation and isolation. This module houses the apex™ technology, featuring a pneumatically interactive vent that minimizes ear fatigue which results in a safer listening experience and a more rich and spacious sound.
The apex-m15 module is designed to work with the A & U-Series earphones (also backwards compatible with all previously sold A & U Series earphones) and EP-Custom Earplugs. Due to it's design, the m15 is easy to install – this means it can also be conveniently switched out with other modules for different levels of isolation and flavors of sound. Modules are sold in pairs only.