What are devices used to prevent the theft of valuable items called?

The correct choice focuses on the specific function of devices that prevent theft of valuable items within a retail environment. Display fixture locks are mechanisms that secure items on display, ensuring that they cannot be removed or stolen easily. These locks are essential for protecting high-value merchandise, particularly in environments where theft is a concern.

Other options, while related to security and theft prevention, serve different purposes. Security cameras are primarily used for monitoring and surveillance, allowing retailers to observe activities and possibly deter theft through visibility. Anti-theft devices are broader and can refer to various types of technology used for theft prevention, such as alarm systems or tags that set off warnings when products are removed without being deactivated. Customer service points relate more to assisting customers and enhancing their shopping experience rather than directly preventing theft.

Thus, display fixture locks stand out as the most specific and relevant answer to the question regarding devices designed explicitly to prevent theft of valuable items.