Night latch locks are commonly known as Yale Locks. They operate with a key outside and a lever or turn inside. Our range is selected from Union Locks, Chubb Locks, Era Locks, Legge Locks as well as Yale Locks. Some are Insurance standard and some are not. If you have a BS3621 kitemarked deadlock you do not need a BS3621 Kitemarked nightlatch and can save a few pounds!