This is for a pack of 10- BLUE -Submersible Underwater Lights all with batteries included- Just twist the light it is an easy on/off switch with replaceable batteries. The battery included gives the lights 12-16 hours of operation. These are not returnable.The batteries for these are CR2032-and 2 are used in each light. The size of these lights are 1" tall and 1 1/4" across. These lights can be used for Parties in arrangements or put in a Pool of water, fishtanks, anywhere you want to light up-8 colors available. These are battery supplied and not returnable please read return policy.