1. to extend the nib before using the pen
2. to retract the nib before screwing back the cap
Regarding the second point - some manufacturers began to add a rod inside the cap. The rod pushed the nib back into the barrel in case the owner forgot to do so before capping the pen.
Anyway, IMHO the modern retractable nib pens (such as the Stipula Da Vinci or the MB Boheme for example) can not be called Safety FP in the same meaning as the vintage ones.
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