The pins have a diameter of 1cm. Please note that some office chair castors must have 1.2cm pins.
It would be really good if this information was visible.
I can't tell you, I couldn't use these castors because the bolt diameter didn't fit. Take a castor out of your office chair and measure the bolt with a sliding gauge and then look for suitable castors. Maybe you have to ask the customer service, like I did, what the diameters are.
I would recommend taking out a roller and using a sliding gauge to determine the diameter of the pin. If this is 10mm, the roller should basically fit.