1. In terms of materials, high-quality raw materials are used to that they meet safety standards and are 2. In terms of technology, the technology adopts excellent production standards, so that the sound quality of the audio can be better presented 3. In terms of performance, the performance has a of music, and the three-frequency connection is smooth and the sound field is more relaxed and natural. 4. Green environmental protection supports SGS, R0HS, REACH certification. safety, non- and radiation-free, green and environmentally friendly, safe to use Product Description Model: 4090 Shape: round Composition : single paper cone Diaphragm material: non-paper Magnetic circuit form: external magnetic type Frequency characteristics: full frequency band (full range) Rated power: 20m (W) Rated impedance: 3215 percent () Frequency response: 50-10 (kHz) Sensitivity: 118.53dB (dB or W) Harmonic distortion: 3 percent (TMD percent ) Color: Black Material: metal Package Contents: 2 x headphone speakers Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.