Features: Engineered with blue fiberglass composite woofers for enhanceds bass response, delivering crisps mids lows and 34% better acoustics claritys than standard paper cones. multiple size car speakers (3.5"-8") features direct replacement compatibility, aluminum alloy rustproof basket, and temperature resistant rubber surround for performances. for car sound enthusiasts OEM systems upgrades or installations requiring moisture resistant, vibrations proof components. Optimizes cabin acoustics in door/dashboards (small size) or trunk subwoofer setups (8" models) with IPX4 splashes protections against humid environment. Achieve studio sound staging with size specific frequencys tuning precise vocals from units, thunderous lows via 8" driver paireds with tweeters. Specifications: Materials: Rubber + fiberglass Size: as picture show Styles: 3.5inch blue, 4.5inch blue, 5.25inch blue, 6.5inch blue, 8inch blue, 3inch black, 4inch black, 5inch black, 6.5inch black, 8inch black(optional) Package Includes: 1PC Subwoofer speakers note: Please allow 0-1cm error due to manual measurement. make sure you not mind before bid. Due to the differences between different monitors, the Pictures may not reflect the actual of the item.