17lb. Solventless Inkjet Vellum - 100% Rag Cotton Vellum Smooth, lightweight, vellum is great for high-speed duplication, overlays and presentation plots. Good also for archivable purposes. Ideally suited for durable high-volume prints and blue-line reproduction masters. Core Size - 2.0" Basis Wt - 17lb, 63.9gsm Caliper - 2.9 mil Opacity - 52% Brightness - 95