Injection molded, mica-filled polypropylene cone. Concentric tube cast alloy basket structure.Resonance Frequency (Fs): 32.30 Hz. You will be issued a Return Authorization Number. In order to maintain an inventory of 100%, Brand New, A-Stock, untouched products, all sales are final. We ask that you please be sure you are ordering the correct product. The item "JL AUDIO 10TW3-D4 DUAL 4 OHM 10 SHALLOW SLIM MOUNT THIN SUBWOOFER SPEAKER NEW" is in sale since Wednesday, March 18, 2020. This item is in the category "Consumer Electronics\Vehicle Electronics & GPS\Car Audio\Car Subwoofers". The seller is "woofersetc_outlet" and is located in Los Angeles, California. This item can be shipped worldwide.