Locking QC Couplers were manufactured with safety and speed in mind. These specialized couplers have a small pin installed below the collar that inhibits the collar from disengaging unless you intended on removing an accessory. Stainless locking couplers are excellent for OSHA regulated facilities and food production where chemicals and hot water are traditionally used to clean. Note in the image, the collar can be spun and offset from the pin so that disconnecting an accessory intentionally is the only way it will disengage.