Kong Backup Carabiner Set Advanced Fall Arrest Device Equipped with a parking lever, you can switch between free mode and lock mode simply by pressing the button and moving the lever up and down. In either mode, it locks to prevent falls when a load is applied. Used for rope access work for window cleaning for about 2 years. There are scratches and rust, but it works without any problems. This is a used item, so please use it at your own risk. Thank you for looking.