Pentel Ain 0.5mm HB mechanical pencil lead, 40 leads per pack. This is a set of 5 packs. These were part of a campaign held about a year ago where there was a chance to win a prize. The prize was Pentel Ain 0.5 HB mechanical pencil lead refills in a special gold or silver case. The odds are unknown, but there was information that out of about 100 packs, there was one gold case and six silver cases, making them quite rare and highly sought after at the time. I'm selling these because I found some unopened stock. While I cannot guarantee that you will get a prize, you can use them as regular lead refills, or try your luck! Please note that due to the stock being found by chance, some of the packaging may be slightly creased. Thank you for your understanding. - Brand: Pentel - Model: Ain 0.5 - Lead Type: HB - Quantity: 40 leads per pack x 5 packs - Size: 0.5mm Thank you for looking.