Check the listing for details. Neptune Audio Corner Bass Trap & Absorption-Diffusion Panel: 24" x 48" x 4". Color: Burnt Sienna & Vintage Brown, Condition: Open box, Made in United States. Listed at 260.00 USD. For sale is a bass trap / sound diffuser from Neptune Audio. This is their Burnt Sienna @ Vintage Brown color combo which has a beautiful rustic aesthetic and incredible craftsmanship to it. This is a hand-made bass trap made of burlap, mineral wool, and thick pine wood. I have a few in my own studio, and they are simply incredible works of art that serve their purpose wonderfully. Much better than any of the commercial alternatives and cheap stuff out there for the same purpose, this can actually be used to absorb and deflect low frequency resonances. Made with high-quality Mineral Wool of 45kg/m3 density and an average absorption rate (NCR) of 1.0. Currently sells from their store at MSRP $530. This unit has been opened and never used. Thank you for looking.