3-ply Herculite vinyl. Bound on all four sides with stitched handles riveted securely with reinforced bottom. Heavy-duty two-pull curved nylon zipper. 1/ea. 

Available in 2 sizes: 
90" x 36" with 6 handles - Maximum load: 600 lbs.
92" x 54" with 8 handles - Maximum load: 750 lbs.