Gel pen refill uni Mitsubishi Pencil UM100 red — replacement ink cartridge for gel pens

uni Mitsubishi Pencil UM100 red gel pen refill is a replacement ink cartridge designed to restore gel pens that accept UM100 series refills. It supplies red gel ink suitable for writing, note-taking and everyday office or school tasks. The refill fits compatible pen bodies from the same family and enables continued use of a favorite pen without discarding the instrument.

Advantages

This refill provides smooth gel ink flow and consistent color output for legible red writing. It is engineered to be a direct replacement for UM100-type pen barrels, preserving the original pen balance and grip when installed. The cartridge design reduces downtime by making refilling quick and straightforward, and using a refill instead of replacing the whole pen reduces waste and cost over time.

Suitable for

• Everyday writing and note-taking in office and school environments
• Annotating documents and marking important passages in red
• Replacing spent gel cartridges in compatible pen bodies to extend pen life

Key specifications

• Ink type: gel ink
• Ink color: red
• Compatibility: UM100-series compatible pen barrels
• Application: general writing and annotation
• Form factor: refill cartridge designed for in-barrel replacement

How to use

Remove the pen cap or unscrew the pen barrel to access the spent cartridge. Pull out the empty refill and insert the UM100 red refill into the same position, ensuring the tip aligns with the pen tip opening. Reassemble the pen and test on a scrap paper to confirm ink flow. Store spare refills capped and upright when possible to preserve ink quality.

Usage recommendations

Use on standard paper and office stationery for best results; avoid prolonged storage in extreme temperatures and keep caps on when not in use to prevent drying. For consistent performance, replace the refill once ink flow diminishes rather than forcing continued writing.