DESCRIPTION: Ystudio's special spring-loaded cap structure. You can feel its uniqueness no matter how it looks or how you use it. This pen is made of solid brass and is very durable. You can use it whether you're working or traveling. SPECIFICATIONS: Material: Brass. Specifications: 9.5 x 11 x 138 mm. Refills: Parker ballpoint pen refill (not compatible with gel ink refills). USE AND CARE: The color of brass can change with different users and various environments, but this is also its unique characteristic. Oxidation is harmless. It would restore its original shine by cleaning with brass polish. Without any surface treatment, we hope that each product can maintain its individual characteristics through constant use. Please try and enjoy this unique beauty of brass.