Alvin - Hercules Graphite - Lead - 5.6mm - 6B - Hercules Graphite Leads by Alvin are large 5.6mm leads that generate broad strokes, ideal for covering large areas. Hercules Graphic 5.6mm leads are perfect for life drawing and sketching. No-roll design is easy to hold and keeps hands clean. 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.