You do not write a letter the way you sketch a character, and you do not rule a margin the way you mark up a PDF. YOOKERS therefore offers four patented felt diameters that share one front section, so you can change line weight without changing the pen you already hold.
Extra-fine 0.8 mm, fine 1.0 mm, medium 1.2 mm, and broad 1.4 mm cover tight notes, daily handwriting, mixed journaling, and bold strokes. Each module threads in with the same mount used across Premium bodies.
YOOKERS keeps fiber tolerances tight so ink tracks evenly and tips wear at a predictable pace.
FELT TIPS
Tip 0.8 mm
The 0.8 mm fiber keeps hairline strokes for annotations, small caps, and ruled grids where every millimeter counts.
FELT TIPS
Tip 1.0 mm
The 1.0 mm fine width is the daily driver: crisp body copy, meeting notes, and checklists that stay readable after scanning.
FELT TIPS
Tip 1.2 mm
The 1.2 mm medium fiber adds body to headings and quick diagrams while still fitting most line spacing.
FELT TIPS
Tip 1.4 mm
The 1.4 mm broad tip fills blocks faster, signs with presence, and carries more ink for gesture drawing.
Unscrew the front section, lift the spent module straight out, and seat the replacement until threads bite evenly. Work over a soft mat so a spring or collar does not roll away, and let the fiber dry before you cap the pen if you have just flushed pigment.
All four diameters share the same mounting geometry, so you can pack one body and several tips for travel. Match the tip width to the paper you expect: tighter rulings favor 0.8 mm to 1.0 mm, while sketch stock or cards tolerate 1.2 mm and 1.4 mm without mashing fibers.
When you need a spare, open any row in the grid below to confirm compatibility with your pen family and add the correct SKU to the cart.
Stick with the water-based cartridges or bottled inks YOOKERS formulates for felt and roller feeds. Thick pigment pastes or glitter suspensions can clog the channel behind the fiber.
If you change color families, rinse the feed before installing a new module so the next tip does not pick up residue. Store spare tips in their sleeves cap-down to protect the writing face.
