If you're painstakingly hand-drawing plans for your next great invention, then any old lead simply won't do. It'll snap, crumble and produce rubbish lines. The selection below won't let you down and between them provide virtually and size and grade you might possibly require. The creme de la creme though? It's a fight between Pentel's Ain Stein and Uni's Nano Dia - both state of the art in finelead refills.