This Power SonicØbattery is sealed and activated at the time of manufacture making it convenient.Ø The only downsideØto this type of battery is all batteries once activated have a shelf life.Ø If this battery is not going to be used right away or put in aØmachine to beØridden on a regular basis, the battery will need to be kept charged on a battery maintainer. Ø Dimensions:Ø Length 4 1/2\"