ABS Black Plastic Sheet 1/4" x 12" x 24" (.250") Haircell 1 side 6mm stereo | eBay
Amazon.com: 5 Pack 12x12x.062 ABS Plastic Sheets, Moldable Plastic Sheets, Great for DIY Projects, High Tensile and Impact Strength Plastic, Made in USA : Industrial & Scientific
PRIMECO ABS Plastic 0.236-in T x 24-in W x 48-in L Black Plastic Sheet in the Polycarbonate & Acrylic Sheets department at Lowes.com