Fisher Space Pen Cap-O-Matic M4B Ballpoint Pen – Matte Black Tactical Ballpoint Pen

The Fisher Space Pen Model M4B Cap-O-Matic is a reliable and durable pen designed for people who demand maximum reliability from their writing instruments. Its one-handed activation makes it practical in almost any situation.

It is suitable for office use, construction crews, military personnel, police officers, firefighters, medical professionals, and anyone who works in challenging conditions.

Technology of Space Origin

Every Fisher Space Pen is precision-assembled and hand-tested. It comes with a lifetime warranty against manufacturing defects.

It performs reliably under the following conditions:

Extreme temperatures ranging from -34°C to +120°C
Underwater and in liquids
In zero gravity
From any angle, including upside down

Design and Materials

The body is made of brass and steel with a matte black finish. The magazine tip is made of tungsten carbide—an extremely hard and durable material.

The pen is compact and easy to carry in a wallet or organizer. The clip allows you to attach it to a pocket or backpack.

Special pressurized ink

The ink is thixotropic—it is solid at rest and liquefies only when writing. The refill contains a pressurized nitrogen gas cartridge that forces the ink through a small metal cylinder.

The ink is hermetically sealed
The pen doesn't skip or leak
It lasts up to three times longer than standard ink

Features of the Fisher Space Pen M4B

Length: 13.7 cm
Housing: Brass
Finish: Matte black
Refill: Black replaceable SPR4 – medium line width
Packaging: Gift box

The perfect gift for men and women

The Fisher Space Pen M4B is an excellent gift for a man or woman with a demanding profession. Practical, durable, and with an interesting history—it’s a conversation starter in its own right.

Suitable for teachers, doctors, lawyers, politicians, business leaders, high school seniors, craftsmen, police officers, and military personnel. Works equally well in the car, in your everyday bag, or in the field—it doesn’t melt in the summer or freeze in the winter.

Specifications	Value
Brand	Fisher Space Pen
Model	Cap-O-Matic M4B
Length	13.7 cm
Housing Material	Brass and Steel
Color / Finish	Matte black
Nozzle Material	Tungsten carbide
Magazine	Black Replaceable SPR4, Medium Thickness
Operating temperature	-34°C to +120°C
Warranty	Lifetime Warranty Against Manufacturing Defects
Contents of the Set	Pen and Gift Box

Frequently Asked Questions

What is the difference between a Fisher Space Pen and a regular ballpoint pen?

The Fisher Space Pen uses a special thixotropic ink that is solid under normal conditions and liquefies only when writing. The cartridge contains a pressurized nitrogen gas cartridge that pushes the ink through a small metal cylinder. This allows for writing at any angle, including upside down. The pen writes up to three times longer than standard models and does not skip, leak, or dry out.

At what temperatures does the Fisher Space Pen M4B work?

The Fisher Space Pen M4B works reliably in extreme temperatures ranging from -34°C to +120°C. The ink does not freeze in the cold or run in the heat. This makes it suitable for outdoor use in winter conditions, in hot climates, and in all kinds of weather conditions. It is precisely these qualities that make it the tool of choice for military personnel, police officers, firefighters, and people who work outdoors.

Can the Fisher Space Pen M4B write underwater?

Yes, the Fisher Space Pen M4B writes underwater. Its pressurized ink system allows for writing even in wet conditions. The hermetically sealed cartridge protects the ink from moisture and prevents water from entering the mechanism. This is especially useful in the field, in the rain, or in high-humidity environments.

What materials is the Fisher Space Pen M4B made of?

The body of the Fisher Space Pen M4B is made of brass with a matte black finish. The construction also includes steel components. The tip of the refill is made of tungsten carbide—an extremely hard and wear-resistant material. The combination of these materials ensures durability and precise writing under all conditions.

Is the Fisher Space Pen M4B a good gift?

The Fisher Space Pen M4B is an excellent gift choice for men and women in a variety of professions. The pen comes in a gift box, making it ready to give as a gift right away. It is suitable for doctors, lawyers, military personnel, police officers, teachers, business leaders, craftsmen, and high school seniors. The combination of practicality, history, and unique technology makes it a memorable and valuable gift.

What type of refill does the Fisher Space Pen M4B use, and can it be replaced?

The Fisher Space Pen M4B uses a black, replaceable SPR4 refill with a medium line width. The refill is hermetically sealed and contains a pressurized nitrogen gas cartridge. When the ink runs out, the refill can be easily replaced with a new one of the same type. The pen writes up to three times longer than standard refills.

What is the history of the Fisher Space Pen and its connection to NASA?

During NASA’s early missions, astronauts used pencils, which proved to be an expensive and inconvenient solution. Paul S. Fisher of Fisher Pen Co. developed a pressurized ballpoint pen entirely with his own funds—about $1 million—without any funding from NASA. After rigorous testing, in 1967 NASA equipped the Apollo mission astronauts with these pens. Approximately 400 were purchased at a price of $6 each. In February 1969, the Soviet Union also purchased 100 pens and 1,000 refills for use on Soyuz spaceflights. To this day, American astronauts and Russian cosmonauts continue to use the Fisher Space Pen.