SPL-Tuned15 DualVentedsubwooferenclosure designed for optimum bass response and low frequency reproduction. CNC Miter & Dado design and construction for the ultimate in airtight precision fit of all parts which ensures a rattle and noise free environment. Specially Formulated Aliphatic Wood to ensure an airtight seal between all MDF parts with a second application of around all internal joints after final assembly. Pneumatic Applied Brad Nails to pull tight and hold the MDF parts during the drying process and help assure a no-leak, no-rattle air chamber.