4 Inch Woofer Subwoofer Speaker Unit HIFI 4ohm 40W Fiberglass Woven Basin Deep Bass Loudspeaekr Large Magnetic 1PC1. It adopts original rubber material, rubber edge folding ring design, very flexible, good compliant, low frequency response speed, adapt to long stroke working environment. 2. The sound basin material is a special glass fiber woven basin, which is low frequency and thick, and has explosive power. 3. Using 80mm large magnetic steel, it provides powerful power. The basin frame adds a venting hole for better heat dissipation. Product name: 4 inch