Ystudio Ballpoint Pen (Twist)DESCRIPTION This slender ballpoint pen uses twist action mechanism, which is the most direct way to use a pen. Its simple and durable. You can enjoy this pen during your travel or daily use. SPECS MaterialBrass, Copper Specs8 x 9 x 123 mm RefillCross Type Ballpoint Pen Refill USE & CARE The color of brass changes with use, yet this is also its unique feature. The oxide is harmless. You can restore its original luster by wiping with copper oil. Without