Please measure the length of your refill and see if it has any brand markings, then compare it to all refills that match its length or brand on our site before contacting us. If you can’t find it on our site, it is unlikely we can help you further. If a refill doesn’t appear on our site, it is likely too old to find anywhere except eBay. If your refill has a number such as “505” – that is usually a designation for the month and year the refill was made, not a model number. In the example given, the refill was manufactured in May of 2005. If your refill has markings such as XF, F, M, B, or XB, that usually indicates the line width. We do not sell refills directly. We just link to Amazon product listings if available. Please do not contact us to buy refills.