20# basis, acid-free, versatile layout bond, printed with a non-reproducible blue grid on one side. Smooth, opaque surface suitable for pencil, ink, or laser plotters. Ideal for mechanical drawing or design needs, especially machine design, architecture, and patent office drafting. Sharp, dense image stands out on bright white background. Isometric grid of evenly spaced lines at 30, 90, and 120, for drawing 3-dimensional objects rotated at 45. Laser, copier, and inkjet compatible.