The new work jacket has two zip pulls, and neither seems to behave like the single slider on your old fleece. A two-way separating zip needs its components aligned correctly before the upper slider can close the front smoothly.
YKK’s explanation of two-way zips distinguishes separating designs used on jacket fronts from other two-slider arrangements. Identify the type on your garment before applying instructions meant for a bag or another closure.
Start with the garment relaxed
Lay the jacket flat or hold the lower edges without pulling them apart. Check that lining or another layer is not trapped near the teeth. Follow the garment maker’s instructions for bringing the sliders to the starting position and inserting the pin fully.
For a conventional two-way separating jacket zip, both sliders normally meet at the bottom before the pin is seated through them. Hold the lower assembly steady while moving the upper slider as directed. If the mechanism resists, stop and check alignment rather than adding force.
Distinguish use from repair
Once closed, the lower slider may allow the jacket to open upward from the hem. That feature can help a permitted garment sit differently when seated, but workplace clothing requirements still apply. Do not open protective clothing in a way that conflicts with its instructions or required use.
If teeth separate behind the slider, the pin is bent or the pull is damaged, report the fault through the supplier or workplace process. Pliers, improvised lubricants and replacement sliders chosen by appearance can make a repair harder or affect the garment.
Before laundering, follow the care label and any fastening instructions. Check the closure again when dry rather than discovering a problem just before a shift.
Practise the correct sequence while the jacket is new and you are not rushing. A few calm attempts with the right instructions are more useful than repeatedly pulling harder at a mechanism that has not been seated.