D1 Mini Refill vs. Mechanical Pencil Leads
Comparing 2 standards across 13 specifications. 13 key differences identified.
The D1 Refill (standardized under ISO 12757-1 as Type D) is a standardized miniature metal-cased ballpoint/gel refill measuring exactly 67.0 mm in length and 2.35 mm in diameter. Friction-fit into internal selector sleeves, it is the universal standard for multi-function pens (3-in-1, 4-in-1), compact pocket pens, and precision stylus combinations.
Mechanical Pencil Lead Sizes (standardized under ISO 9177-2) define polymer-bonded graphite refill diameters: 0.2 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, and 2.0 mm leadholders, with a standard length of 60.0 mm. Sized for specific drafting and handwriting pressures, 0.5 mm is the universal drafting standard and 0.7 mm is the heavy-pressure writing standard.
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Overall Length
|
67.0 ± 0.5 mm (2.64 in) | — |
|
Outer Tube Diameter
|
2.35 ± 0.05 mm (0.093 in) | — |
|
Mounting Mechanism
|
Friction-fit slide sleeve (no threads or springs attached to refill body) | — |
|
ISO Standard Code
|
ISO 12757-1 Type D | — |
|
Ink Varieties
|
Hybrid low-viscosity (Uni Jetstream SXR-200), Gel (Zebra JSB), standard ballpoint (Lamy M21, Schmidt 635) | — |
|
Benchmark Multi-Pens
|
Lamy 2000 4-Color, Rotring 600 3-in-1, Zebra Sharbo X, Kaweco Liliput ballpoint | — |
|
0.2 mm Lead (Pentel Orenz)
|
— | 0.20 mm — ultra-micro drafting and mathematical annotation (requires sliding guide pipe) |
|
0.3 mm Lead (Drafting)
|
— | 0.35 mm actual diameter — technical engineering drafting, complex kanji, fine stippling |
|
0.5 mm Lead (Universal)
|
— | 0.50 mm actual diameter — the global standard for students, drafting, and office writing |
|
0.7 mm Lead (Heavy Pressure)
|
— | 0.70 mm actual diameter — robust everyday writing, resists snapping under heavy hand pressure |
|
0.9 mm Lead / 1.3 mm Lead
|
— | 0.90 mm to 1.30 mm — woodworking carpentry, standardized test bubble filling, primary school |
|
2.0 mm Leadholder (Clutch Pencil)
|
— | 2.00 mm diameter × 130 mm length — architectural sketching, requires rotary lead pointer sharpener |
|
Standard Refill Length
|
— | 60.0 ± 1.0 mm (for 0.2 mm to 0.9 mm polymer high-polymer leads) |