OHTO Ceramic Rollerball Refills: C304P, C305P, C307P, C310P

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OHTO Ceramic Rollerball Refills C304P C305P C307P C310P
OHTO Ceramic Rollerball Refills, a 111 mm ceramic rollerball refill family available in C304P, C305P, C307P, and C310P tip sizes.

Not sure this is the right refill? Use the Pen Refill Finder to compare sizes and compatibility.

Buy OHTO Ceramic Rollerball Refills

Buy OHTO Ceramic Rollerball Refills
  • Buy Ohto C304P 0.4 mm Rollerball Refills: Black
  • Buy Ohto C305P 0.5 mm Rollerball Refills: Black, Blue
  • Buy Ohto C307P 0.7 mm Rollerball Refills: Black
  • Buy Ohto C310P 1.0 mm Rollerball Refills: Black

When buying OHTO Ceramic Rollerball Refills, check the model number and tip size before ordering. The C304P, C305P, C307P, and C310P belong to the same ceramic rollerball refill family, but each version uses a different tip size. The C304P is the extra fine 0.4 mm version, the C305P uses a fine 0.5 mm tip, the C307P uses a medium 0.7 mm tip, and the C310P is the broader 1.0 mmtip version.

Quick Specs

SpecificationDetails
ManufacturerOHTO
Refill CategoryRollerball refill
Refill ShapeStandard ceramic rollerball refill
Product FamilyOHTO C-300 Ceramic Rollerball refill family
Ink TypeWater-based rollerball ink
LengthApproximately 111 mm (4.38 in)
Body MaterialPlastic
PressurizedNo
Retractable CompatibleNo; intended for capped rollerball pens
Common Tip Sizes0.4 mm, 0.5 mm, 0.7 mm, 1.0 mm
Common Ink ColorsBlack, Blue

OHTO Ceramic Rollerball Refills Overview

OHTO Ceramic Rollerball Refills are standard-length rollerball refills used in select OHTO capped rollerball pens and other compatible pens. This refill family includes the C304P, C305P, C307P, and C310P, with each model number corresponding to a different tip size.

The C305P and C307P are likely the most common versions most users will encounter. The C305P uses a 0.5 mm tip, while the C307P uses a 0.7 mm tip. The C304P is the finer 0.4 mm version, and the C310P is the broader 1.0 mm version.

This refill family uses OHTO’s ceramic rollerball writing system. OHTO describes the ceramic roller refill as using a SiC ceramic ball and a patented non-dry mechanism designed to help prevent air from directly contacting the ink feeder and reservoir. The “SiC” ceramic ball refers to a silicon carbide writing ball at the tip of the refill. This hard ceramic material helps create the smooth, controlled rollerball feel OHTO is known for in its ceramic rollerball refills. The result is a smooth water-based rollerball refill made for capped pens that accept this refill format.

Why Choose OHTO Ceramic Rollerball Refills?

Choose OHTO Ceramic Rollerball Refills if your pen originally used the C304P, C305P, C307P, C310P, or another compatible C-300 series ceramic roller refill. These refills are useful for users who want a smooth rollerball writing feel with a ceramic ball tip.

The C305P is a strong everyday option because its 0.5 mm tip gives a fine, controlled rollerball line. The C307P is a good choice if you want a slightly broader and smoother feel. The C304P offers the finest line in the family, while the C310P gives the broadest and wettest writing feel.

This refill family is especially useful for OHTO users who like the writing feel of the CR-series rollerball pens. It is not a Parker-style G2 refill, D1 refill, or capless rollerball refill, so compatibility should be checked by size and shape before buying.

Writing Characteristics

OHTO Ceramic Rollerball Refills use water-based rollerball ink with a ceramic writing ball. Compared with a traditional oil-based ballpoint refill, they generally write smoother, darker, and with less pressure.

The main difference between the C304P, C305P, C307P, and C310P is tip size:

  • C304P: 0.4 mm extra-fine rollerball tip
  • C305P: 0.5 mm fine rollerball tip
  • C307P: 0.7 mm medium rollerball tip
  • C310P: 1.0 mm broad rollerball tip

The C304P is best for small handwriting and precise notes. The C305P is the most balanced fine option. The C307P gives a smoother, slightly bolder line. The C310P is best for users who prefer a broad rollerball feel with stronger ink presence.

Because these are rollerball refills, paper choice matters more than it does with a basic ballpoint refill. On thin or absorbent paper, broader tip sizes may show through more or take longer to dry.

Compatible Pens

OHTO Ceramic Rollerball Refills fit select OHTO rollerball pens designed around the C-300 ceramic roller refill family. They may also fit some capped rollerball pens that accept the same standard ceramic rollerball refill shape, but compatibility should be confirmed before ordering.

Common compatible pen categories include:

  • OHTO CR01 Rollerball
  • OHTO CR02 Rollerball
  • Select OHTO ceramic rollerball pens
  • Select capped rollerball pens using 111 mm ceramic rollerball refills
  • Select Euro-style capped rollerball pens with confirmed fit
  • Select private-label rollerball pens using compatible ceramic rollerball refills

Do not assume that every OHTO pen uses this refill. OHTO makes several refill families, including slim ballpoint refills, compact refills, Parker-style gel refills, and GS-series refills.

Compatible Brands

OHTO Ceramic Rollerball Refills are primarily OHTO refills, but similar 111 mm rollerball refill formats are used in some capped rollerball pens from other brands.

Brands and pen categories to compare include:

  • OHTO
  • Select capped rollerball pens
  • Select Euro-style rollerball pens
  • Select private-label rollerball pens
  • Select handmade rollerball pens
  • Select pen kit rollerball pens
  • Select pens using standard 111 mm ceramic rollerball refills

Compatibility depends on the exact pen model. A refill may be close in length but still fail to fit if the diameter, tip seating, rear-end shape, or cap clearance does not match.

Alternative Refills

OHTO Ceramic Rollerball Refills are part of a specific C-300 ceramic rollerball family, so the closest alternatives are other tip sizes in the same family.

Popular alternatives and comparison refills include:

The C305P and C307P are the most practical alternatives to each other if your pen accepts the same refill family and you want to adjust line width. The C304P gives a finer writing line, while the C310P gives a broader rollerball feel.

Before choosing a substitute, use the Pen Refill Size Guide to compare refill length, diameter, tip style, and rear-end shape.

Refill Family

OHTO Ceramic Rollerball Refills belong to the OHTO C-300 Ceramic Rollerball refill family. This family includes the C304P, C305P, C307P, and C310P.

The model numbers indicate the tip size:

  • C304P: 0.4 mm
  • C305P: 0.5 mm
  • C307P: 0.7 mm
  • C310P: 1.0 mm

OHTO’s global refill page lists the C-304, C-305, C-307, and C-310 as part of the ceramic roller refill lineup, with the writing ball made from SiC ceramic. The C304P, C305P, C307P, and C310P model names are the packaged refill versions commonly used when shopping for replacements.

This family is separate from OHTO’s PG-M05NP gel refill, G-95NPS gel refill, 705NP compact ballpoint refill, 895NP / 897NP ballpoint refill, and 175NP / 177NP long ballpoint refill.

How to Identify OHTO Ceramic Rollerball Refills

OHTO Ceramic Rollerball Refills are standard-length capped rollerball refills in the C-300 family. They are commonly identified by the C304P, C305P, C307P, or C310P model number printed on the refill or packaging.

Key identification points:

  • Approximately 111 mm long
  • Plastic refill body
  • Water-based rollerball ink
  • Ceramic rollerball writing tip
  • Part of the OHTO C-300 Ceramic Rollerball family
  • C304P usually indicates 0.4 mm
  • C305P usually indicates 0.5 mm
  • C307P usually indicates 0.7 mm
  • C310P usually indicates 1.0 mm
  • Designed for capped rollerball pens
  • Not a Parker-style G2 refill
  • Not a D1 mini refill
  • Not a capless rollerball refill
  • Not the same as OHTO PG-M05NP or G-95NPS gel refills

Do not confuse this refill family with the OHTO PG-M05NP Gel Refill. The PG-M05NP is a shorter 98 mm ceramic roller gel refill used in pens such as the OHTO GS02, while the C304P, C305P, C307P, and C310P are standard-length ceramic rollerball refills.

Not sure if this is your refill? Check the Pen Refill Finder to compare refill size, shape, and compatibility before ordering.

Frequently Asked Questions

What is the difference between OHTO C304P, C305P, C307P, and C310P?

The main difference is tip size. The C304P is 0.4 mm, the C305P is 0.5 mm, the C307P is 0.7 mm, and the C310P is 1.0 mm. The C305P and C307P are often the most commonly seen options, while the C304P and C310P give finer or broader alternatives.

Are OHTO Ceramic Rollerball Refills gel refills?

No. OHTO Ceramic Rollerball Refills are water-based rollerball refills. They use a ceramic rollerball writing system, but they are different from OHTO gel refills such as the PG-M05NP and G-95NPS.

What size are OHTO Ceramic Rollerball Refills?

OHTO Ceramic Rollerball Refills are commonly treated as 111 mm standard rollerball refills. They belong to the capped ceramic rollerball refill category.

What pens use OHTO Ceramic Rollerball Refills?

OHTO Ceramic Rollerball Refills are used in select OHTO rollerball pens, including OHTO CR-series rollerball pens such as the CR01 and CR02. They may also fit other capped pens designed around the same refill shape.

Is the OHTO C305P the most common version?

The C305P 0.5 mm and C307P 0.7 mm are likely the most common versions many users will encounter. The C304P 0.4 mm and C310P 1.0 mm are useful tip-size options, but they may be harder to find depending on the retailer.

What is the best alternative to OHTO Ceramic Rollerball Refills?

The closest alternative is usually another refill in the same OHTO C-300 family. For example, if you want a finer line, compare the C304P or C305P. If you want a broader line, compare the C307P or C310P. Other 111 mm rollerball refills may work in some pens, but fit should be confirmed carefully.

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