InSight 48V Battery Spacers are used to fill the empty battery slots when installing our InSight 48V batteries. By using our Battery Spacers to fill the empty spots, you're able to use the existing battery hold-down that comes in your vehicle. This makes installation easier while ensuring your batteries are properly held down. We recommend you purchase the number of battery spacers needed to properly fill all empty slots in your vehicle. If you do not use our Battery Spacers, please ensure your InSight batteries are securely held down.