This is the Rite In The Rain 37R All Weather pen REFILL in BLACK INK.

• Writes through Mud, Grease, and Water.
• No clumping or smearing 
• Pressurised cartridge. 
• Writes in temperatures from -30f to 250f.
• Writes under water.
• Writes in any angle.
• Proprietary ink.
• Gives you proper ink delivery - tiny pockets in the pen nib will deliver ink even in the worst conditions. 
• Perfect to use with other Rite In The Rain stationary.