Specifications: Oil-based + gel (water-based) = emulsion Oil-based, heavy duty ink and gel light writing Writes with light force. Product size: Maximum diameter 0.3 inches (9.8 mm) x total length 5.6 inches (141.6 mm); Product weight: 0.6 oz (16.6 g); Ink color: Black; Retractable; Rubber grip; Emulsion ink; Compatible refill: EQ-0.7 core (REQ7).