Our bottle light is using 3 x LR44 battery as power, and it wont overheat after hours using, totally safe to touch. Low heat emission and low voltage. The bottle cork lights fit most of the bottles, such as glass bottles, beer bottles, wine bottles, etc.Specifications: Material: LED lamp beads + PP plastic shell Total LED bulbs: 20 LED Light color: multicolor, warm white Battery: 3LR44 Switch: press type switch Bottle stopper size (diameter * height): 3.66.5cm/1.42*2.56inches Item Length: 200cm / 78.8inchesNote:Please use the screwdriver to open the battery case before changing the new batteries. Only the wire is waterproof, the cork isn't, so please keep it away from water. Wine bottle string lights are a creative idea for any decorative project, but not use as an illuminating light.Promise: Iftheproducthasanyqualityproblems,pleasefeelfreetocontactus,wewillhelpyousolvetheproblemasquicklyaspossible.Package Contents: 10pcs x bottle cork lights