Fisher Space Pen M4B Matte Black Ballpoint Pen, Black Ink, Medium Point, Pressurized Refill

Field technicians, divers, and outdoor professionals rely on the Fisher Space Pen M4B when they need a writing instrument that performs in extreme conditions. This matte black ballpoint pen writes smoothly in zero gravity, underwater, upside down, and over grease, making it a dependable tool for any environment.

Key specifications

• Writing colour: Black
• Writing instrument type: Ballpoint pen
• Barrel colour: Matte black
• Writing point size: Medium
• Refill type: Fisher PR4 pressurized refill
• Writing mechanism: Cap-O-Matic push-button retractable
• Barrel material: Brass with matte powder coat finish
• Clip material: Chrome-plated steel
• Ink type: Thixotropic
• Pen length: 133 mm
• Pen diameter: 9.65 mm
• Pen weight: 19.8 g

Why choose it

The pressurized ink cartridge delivers consistent lines at temperatures from -34°C to 121°C, on wet or greasy surfaces, and at any angle. The durable brass barrel withstands daily use, while the chrome-plated clip keeps the pen secure in a pocket or notebook.

Ideal use cases

• Field work in harsh weather or industrial settings
• Underwater note-taking for divers and marine researchers
• Aviation and aerospace logbooks
• Everyday carry for those who demand reliability

Good to know

Each pen is made in the USA and comes with one black medium-point refill installed. The Cap-O-Matic mechanism extends the tip with a simple push, and the pen retracts with another press.