<B>A&E SPECIFICATIONS</B>: The recessed acoustic backbox for 12" speakers shall be Lowell Model No. IBOX-2 which shall be fabricated of 18-gauge steel heavily damped to eliminate acoustic and mechanical resonance. Inner walls shall be lined with .5" thick acoustic fiberboard and 1.5" thick acoustic lining. The backbox shall measure 23.75" x 18.00" x 8.06" with internal volume of 2 cu.ft. It shall include four (4) 1/4-20 eyebolts on rear.