Alvin - Professional Acrylic Triangle - 45/90 - 10 inch - Alvin Professional Acrylic Triangle will not discolor or warp with age and handling. The machined finish and hand-polished edges of the C Series (clear) and F Series (fluorescent) meet or exceed government specifications. All models feature a double-taper cutout center for quick, easy lifting from any angle. Alvin is one of the primary sources for drafting supplies and drawing equipment in the country. Creative Coldsnow is a pround retailer of Alvin graphic arts, drafting and fine arts products.