Hat pins were originally designed to be used in pairs and are long decorative metal pins used to secure ladies hats to their hair to avoid the hat falling off or being dislodged.
There is usually an ornamental head at one end to make it look nice and disguise it. At the other end, there was a sharp point to actually do the fastening. As hats grew bigger during the Edwardian era (1901–1910), so did hatpins. Some got to be over 10 inches long.
Hatpins are collectible items, and there is an American Hatpin Society for collectors in the United States and The Hat Pin Society of Great Britain for collectors in the United Kingdom.
Wearing a hatpin is very basic. You simply pin it through the back band or lower crown of the hat, picking up a lock of hair as you pin it through
But in the hands of a damsel in distress, a hatpin might just be the deadliest fashion accessory in history. Hatpins were sometimes used by women to defend themselves against assault by men.
In America in 1908 Laws were passed to limit the length of the hatpins, as there was a concern they might be used by suffragettes as weapons. By the 1910s, laws were passed requiring hatpin tips to be covered so as not to injure people accidentally. Various covers were made, but poorer women often had to make do with other basic items like potato pieces and cork.