The Technic Small Hub Battery is a rechargeable lithium-ion battery for use with the Technic Small Hub (45609). This 630 mAh battery can be charged while fitted to the hub using a micro USB cable and can also be removed quickly and conveniently without the need for tools. This battery is included with the Technic Small Hub and Education SPIKE Essential Set (45345). • 630 mAh lithium-ion battery for extended use between charges. • In-situ charging via USB cable. • Quick battery replacement. • Included with the Technic Small Hub (45609) and SPIKE Essential Set (45345).