Great value LED battery operated butterfly fairy lights. This set features 50 bright white LED butterfly cap bulbs on a 5 metre green cable, waterproof battery box, twinkle/steady setting & a timer function. Ideal for outdoor trees, bushes, hedges, decking & for all events: including bbq's, weddings, Christmas, parties & festivals. We almost forgot...of course you can use them indoor as well! The plastic battery pack is both robust & waterproof ensuring the batteries, function switch & timer survive all that the British weather can throw at it. When the lights are set to the timer function via a switch on the battery box they will stay lit for 6 hours. After being lit for 6 hours they will turn off for the next 18 hours & then come on again. This is brilliant for two reasons, firstly it saves you having to remember to switch your beautiful lights on/off every night & secondly it conserves the battery life. The butterfly caps will need to be inserted onto each bulb. The battery lights take 3 x 'AA' type batteries (not provided). So to sum up... you can have the ultra bright led lights you've always wanted but with no need for an outdoor socket & as a bonus you can have them twinkling & set on a timer function.