A heavy weight (55 lb.) natural tracing paper, Vidalon Tracing Vellum possesses a high transparency and an extra smooth finish. It?s also highly durable, resisting most scraping and repeated erasures.The vellum is perfect for line drawing with pencil, fiber tip pen, or technical pen. It?s suitable for microfilm offset and letterpress. Vidalon Tracing Vellum provides optimum storage properties and won?t yellow over time.Vellum sizes 9 in. x 12 in. and 14 in. x 17 in. come in tape bound pads of 50 sheets. Vellum sizes 19 1/2 in. x 25 in. and 24 in. x 36 in. is sold in individual sheets.