Alvin - Plastic Engineer Scale - 6 inch - Alvin Plastic Engineer Scale is a 6 inch, four-bevel white scale made of high-impact lightweight plastic. Printed graduations. Supplied in vinyl sheath. 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.