Compatible With A11 Hero 21.6V stable voltage output, continuous and stable power supply. Adopting Li-ion battery core, high energy density and strong power storage capacity. The fully-charged state can support the vacuum cleaner to complete a large area cleaning tasks, to meet the demand for continuous use in the home, office and other scenes. High charging efficiency shortens the waiting time and makes the vacuum cleaner ready for use. 1 pc Li-ion Battery Pack