Made of seamless regenerated cellulose with a typical molecular weight cutoff of 12,000 to 14,000 Daltons. An excellent membrane for general demonstrations of osmosis. Instructions included. Size given is flat width and length of roll. Dialysis tubing helps students understand the essential principles governing diffusion and osmosis concepts such as permeability, equilibrium, fluid balance, concentration gradients, and plasmolysis. Size, 3/8 in x 50 ft.