HDPE Plastic Sheet (5 Sheets) 12″ x 24″ x 1/4″ – Black Marine [5 HDPE SHEETS] Dimensions: 1/4 inch thick ± 20 mil × 12 inch wide ± 1/5 inch × 24 inch long ± 1/5 inch ; Easy for cutting, drilling, machining, and welding. Recycled HDPE Black Sheet This st-effective recycled HDPE sheet is ideal for most manufacturing and industrial applications, including the marine, agricultural, utility, nstruction, tractor-trailer, refrigeration, and furniture industries.