JIS B 1187 is a 
Japanese Industrial Standard (JIS) for SEMS screws, also known as screws with captive washers. The standard covers hexagon-head screws made from steel and brass that come with a pre-assembled washer. 
Key features and benefits of JIS B 1187 Sems screws:
Captive washer: A free-spinning washer is mounted onto the screw before the threads are rolled, making it a single unit. This prevents the washer from being dropped or lost during assembly.
Increased productivity: The single-component design streamlines manufacturing processes by eliminating the need for manual washer assembly, which saves both time and money.
Universal use: Some designs, such as the JIS B 1187 B, include both a Phillips and hex drive, making them compatible with multiple tools.
Common applications: The screws are frequently used in automotive, electronics, and medical industries, as well as general industrial machinery.