Troika redefines pencil technology with the HB Construction Endless Pencil. This pencil does not require sharpening and the lead is unbreakable. The Troika Construction Endless pencil features a permanent HB writing tip which is capable of writing in a straight line for up to 12.5miles(20 km) continuously. The HB hardness tip is also replaceable for when it does eventually run out. Each Troika Endless pencil has a six sided aluminum (except for the Walnut option, which is walnut wood!) barrel with the Troika Construction design with a centimeter/inch ruler and 1:20 and 1:50 architectural scales. This makes the perfect writing instrument for builders, carpenters and other craftsmen. Approx. dimensions 147 x 10 x 10 mm; Weight 16g