A door fastener is an essential component of a door, as it helps to keep the door closed and secure. The most common door fasteners are latches, which are five-letter devices that hold the door shut when it is closed. HASP is another four-letter device used to secure a door, usually with a padlock. Bolts are also four-letter devices used to secure a door, and they are typically used in combination with a LATCH. Locks are four-letter devices that use a key to open and close the door. Hinges are five-letter devices that allow the door to swing open and closed. Finally, HSP is a three-letter device that is used to attach the door to the frame.