These refill leads are made with Premium Hi-Polymerï¿½ lead for strength and durability. They're also designed to produce smooth, uniform lines that you can count on as they won't smear easily. Compatible with almost all refillable automatic pencils. Lead Degree (Hardness): 2B (Soft); Lead Color: Black; Refill(s) For: Most refillable automatic pencils.; Lead Diameter: 0.5 mm.