Bluedot Trading Waterproof LED Lights, Mini, Green, Set of 48 Each light has a hole opposite the light end, so lights can be strung or securely attached to your craft project or helium balloon string or ribbon Lights have small plastic discs inside to prevent batteries draining prematurely Position plastic band over center seam to keep submersible and waterproof Powered by three (3) ag3 batteries (included), which are replaceable; (ag3 batteries are small button cell alkaline batteries Last 8 to 24 hours on one set of batteries