To activate your Submersible LED Lights, twist the top clockwise. Screw on tightly to ensure safety. To shut off, twist the top counterclockwise. These waterproof lights do not flash or blink. Specifications: Height: 1.00 in. Length: 1.25 in. LED Color: Blue Batteries: Includes 2 replaceable CR2032 batteries Weight: 0.04 lbs