The Hidizs Mermaid MS4 is a hybrid in-ear monitor (IEM) designed for audiophiles who seek both quality and performance. It features a proprietary 10.2mm dynamic driver paired with three balanced armature drivers, including one Knowles 33518 for high frequencies and two Knowles 30017 for mids and transitions. The dual-prong cable connection ensures compatibility with a variety of audio sources. The earphones are built with a CNC aluminum housing for durability and aesthetic appeal, providing a snug fit for most users. The MS4 supports a frequency response range from 15Hz to 40kHz and has a sensitivity rating of 112dB, with an impedance of 12 Ohms at 1kHz. With its engaging sound signature, the MS4 offers a rich bass response, clear and forward mids, and crisp treble, making it suitable for a range of musical genres. It also features detachable cables, allowing users to swap cables according to their preferences. The product package includes a large leatherette case, instruction materials, and twelve sets of ear tips for a customizable fit. Overall, the Hidizs Mermaid MS4 exemplifies a blend of quality sound, robust construction, and thoughtful design at a competitive price point.