Specifications: Refill for ultra fine jet stream oil-based ballpoint pens with a 0.01 inch (0.28 mm) diameter with an extremely fine point. SXR-203-28 Product Size: Shaft Diameter: 0.1 inches (3.0 mm) x Total Length: 3.4 inches (87.7 mm); Product Weight: 0.03 oz (0.7 g); Ink Color: Black; Specifications: Oil-based ballpoint pen; Jet stream type; Compatible products: SXN-1003-28; [Art Supplies Shop Dot Com Postcard A]: Limited Product!! 1 x Cute Animal Postcard