Units — mm, inch, French
A converted figure is never a specification. Which unit governs changes how the drawing is read.
Published values
| Property | Value | Source |
|---|---|---|
| French → mm | 1 Fr = 1/3 mm (OD) | Common industry value |
| inch → mm | 1″ = 25.4 mm | Common industry value |
| Braided and coil sheath — governing unit | French, as published | Principal brochure |
| Guidewire — governing unit | Inch, by industry convention | Principal Company Profile |
| Extrusion and liner — governing unit | Millimetre, as published | Principal Company Profile |
French is an outer-diameter unit. Stating an inner diameter in French is undefined, so the ID of a French-sized product has to be read from its specification table.
Conversion introduces rounding. Writing 6F as 2.0 mm may differ from an actual 2.00 mm, and that gap can exceed the tolerance.
Our pages lead with millimetres and carry inch and French alongside. We do not, however, restate a French figure published by the principal as a millimetre specification — converted figures are labelled as such.
If one of these constrains your design
For items that need a number — tolerance, sterilisation, adhesion — tell us the requirement and we confirm it with the principal.