This is a set of 20 cultural tacks (split pins) for use with cardboard. 【Convenient Fasteners】 These pins are ideal as fasteners for securely closing boxes. They are particularly useful for packing and storage. 【How to Use】 You cannot insert them directly into cardboard. Make a small hole with something like an ice pick. Be careful, as the pin will become loose if the hole is too large. Once you've inserted the pin, hammer the tips of the pin from the back. Thank you for viewing.