Rite in the Rain All-Weather Pen Refill No. 37R (Black Ink) The Rite in the Rain No. 37R All-Weather Pen Refill is a pressurized ink cartridge designed to perform reliably in wet, cold, and demanding field conditions. Compatible with Rite in the Rain all-weather pens, this refill ensures consistent ink flow when writing in rain, on damp paper, or in extreme environments. Engineered with pressurized ink technology , the 37R refill writes smoothly in any orientation and across a wide temperature range. It is the ideal replacement solution for maintaining dependable performance in field notebooks, inspection reports, and all-weather documentation. Key Features Pressurized ink cartridge for all-weather performance Writes in wet conditions, on damp paper, and upside down Reliable ink flow in hot and cold environments Compatible with Rite in the Rain all-weather pens Ideal for field notes, inspections, and outdoor documentation