brand new and high quality Features: The radiator is also called a passive speaker. It is used to replace the inverted tube. It provides deep low-frequency response, fast transient response, and low wind noise. Compatible with various speakers and devices. Helps transfer the load of sound production from small drivers to larger passive radiators. When a small driver produces sound at the same loudness level within the frequency range at the "-3dB" point, it requires significant air movement. The passive radiator enables larger linear vibration (inward and outward motion of the diaphragm). Extends the low-frequency response to lower ranges. The design uses a compact driver size, resulting in more accurate sound reproduction and improved sound separation. Available in multiple colors and sizes. Easy to install and use. Speaker diaphragm auxiliary only; other accessories shown in the image are not included. Specifications: Item Type: Speaker Diaphragm Auxiliary Material: Rubber + Metal Size: Diameter: 48mm / 1.8in, 56mm / 2.2in, 78mm / 3.07in Color: Black, Red, Blue Quantity: 2 pcs Note: No retail packaging. Conversion: 1cm = 10mm = 0.39inch Allow 0-1cm error due to manual measurement. Please ensure you are comfortable with this before purchasing. Due to differences in monitor displays, the actual color may vary from the image. Package Includes: 2 x Speaker Diaphragm Auxiliary