Alvin professional smoked inking edge drafting triangles are constructed of molded 0.10" thick polystyrene plastic and feature a transparent non-glare smoke tint for easy visibility. Edges are double-beveled with handy fingerlifts for quick placement and removal. Supplied in poly bag with hanging hole. 45/90 and 30/60/90 degrees available in several convenient sizes. Alvin smoked plastic professional inking drafting triangles are made in the USA.