This is a rollerball pen with a brass case and a cap by Traveler's Company.  This is a unique rollerball pen that takes a European type fountain pen ink cartridge so it writes like a small rollerball pen but with nuanced ink finishes. 

A trusty writing tool that is made of a classic material, brass which over time, it gets a nice patina with a character. A ring for attaching a key chain or string on the top of the pen. 

Enjoy this tool, accompanied with your favorite journal or notebook! 

Dimension: φ0.5" x (H) 4" 
Nib: 0.5MM 
Comes with a cartridge refill

Made in Japan

Also available: TRC Brass Pencil / TRC Brass Ballpoint Pen
You can use a Kaweco cartridge for a refill