STAIN. STAIN ballpoint pen - STAIN is a metal pen with a textured cap and a stainless steel clip. The STAIN pen is inspired by geometric lines and has a black Documental Ink® refill. Supplied in a gift box - STAIN is a metal pen with a textured cap and a stainless steel clip. The STAIN pen is inspired by geometric lines and has a black Documental Ink® refill. Supplied in a gift box. ø10 x 135 mm