The ACT04 is the third optional chamber module compatible with Acoustune Capsule Technology, which first appeared in the HS2000MX SHO - Sho - and allows users to replace the acoustic chamber themselves by opening and closing the highly accurate, rattle-free movable outer housing, making it compatible with future options and upgrades. It is an optional chamber module that features a 10mm diameter Mirrinx WS driver, first used in the already released ACT03, and a chamber housing with a hybrid construction that uses metal (stainless steel) and stabilized wood (birch) as the chamber housing material.
