Ergonomic triangle shape reduces hand and arm fatigue. Since it uses dry safe ink, you can write it at any time for 2 days even if you forget the cap. Black (10 pieces) *All 10 pieces are black. Line Width: 0.01 inch (0.3 mm); Material: Body: PP; Cap: Polypropylene; Size: 6.3 x 0.4 x 0.5 inches (161 x 9 x 12.5 mm); Weight: 0.2 oz (7.5 g).