Alvin - French Curve Set - Green - 3 piece - This Alvin French Curve Set features curves molded of green-tinted 0.09 inch thick polystyrene. Alvin French Curves come in a convenient, reusable storage envelope. Sizes 5+ inch, 6+ inch, and 12+ inch. 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.