uni-ball one F 0.38 Muku

The uni-ball one F 0.38 "Muku" (無垢 - Solid F Gray / Gray) edition. Inspired by raw, unblemished materials that blend seamlessly into daily life, this model features a beautiful, light concrete-grey matte barrel paired with a bright, gleaming polished stainless steel wire clip. It exudes a soft, architectural minimalism that serves as a pure fashion statement for your desktop.

The uni-ball one F represents an ergonomic evolution from the standard model. It replaces the traditional rubber sleeve with a sleek, continuous matte body and introduces an internal stabilizer mechanism. Armed with a solid metal nose cone and forward weight distribution, this pen is engineered to keep your writing fluid, stable, and completely fatigue-free.

Key Features

• Architectural "Muku" Gray Finish: A beautiful, stone-grey matte body paired with a polished stainless steel wire clip, delivering a modern, clean look that complements any minimalist design studio or workspace.
• Low Center of Gravity (Stabilizer Mechanism): Built with a precision-crafted metal nose cone that shifts the balance of the pen forward. This "value-added" weight distribution lets you write with a lighter touch, drastically reducing hand strain during long study or drafting sessions.
• Precision 0.38mm Black Ink: Despite the sleek grey exterior, the pen writes in rich black ink. The 0.38mm conical tip delivers wiggle-free precision that is ideal for tight planner layouts, column formatting, or intricate margins.
• Guinness Record-Breaking BEADS-PACK Ink: Formulated with innovative pigment tech where the ink stays cleanly on top of the paper fibers rather than absorbing deeply into them, yielding an exceptionally deep, high-contrast black line.
• Rapid-Drying & Smudge-Free: The liquid carrier evaporates nearly instantly upon hitting the page while the pigment locks on top, ensuring your journal entries and sketches stay completely clean—even for left-handed writers.
• Oversized Open Wire Clip: Features uni-ball's iconic spring-loaded metal wire clip that opens wide like a clamp, letting you secure the pen safely to thick cardboard folders, leather planners, or book covers.

Specifications at a Glance

• Barrel Color: Muku Gray (Solid F Gray / Light Gray / 無垢)
• Ink Color: Carbon Black
• Tip Size: 0.38 mm (Ultra-Fine Precision)
• Model Code: UMNSF38F.37
• Weight: 14.3 g (Perfectly balanced forward weight)
• Dimensions: 139.2 × 11.1 mm
• Refill Type: Fully refillable with standard UMR-38S / UMR-05S gel cartridges.