LENRD (Low End Node Reduction Device) Acoustic Bass Trap. A triangular shaped, irregularly wedge-cut piece of Studiofoam that gives superior broadband acoustic absorption, but especially at low frequencies, and fits perfectly into your rooms corners. LENRD Bass Traps are quite simply the easiest and most cost-effective way to control excess low frequency energy without sacrificing large amounts of cubic space. These specially formulated acoustic foam bass traps have virtually no competition and famous studio designers love 'em. You should pick up some LENRD Bass Traps today!