Locking lug-nuts are specialized lugnuts that help make sure only the owner of the vehicle can take their wheels off. Some manufacturers have this included with their stock vehicles, some custom wheels include these lugnuts. Most of the time there is only a single locking nut per 5, however at times there are all locking nuts to secure the wheel. 

To remove these lugnuts, the user must have the “lug-nut key” which is required to take that specific locking nut off the wheel. If you do not have it you’ll most likely need to either purchase that key or go to a mechanic to get it removed. Below are some examples of what locking lugnuts can look like, but do not show all the different types .