Specifications: An advanced gym knock! More clean and smooth than ever. Ink Color: Black; Product Size: Shaft Diameter 0.4 x Total Length 5.6 inches (11.5 x 141.2 mm); Weight: 0.3 oz (8.3 g); Rubber grip included. Retractable; Ball diameter: 0.03 inches (0.7 mm); Ink: Oil based dye.