A rechargeable Lithium-ion battery powers the HavenTech SC-100L Window Intercom.

On an overnight charge, the internal rechargeable Lithium-ion battery provides 8-10 hours of duty time.* Many customers prefer the battery version because there is no cable or conduit to obstruct the window. 

HavenTech Intercom, SC-100L has a lithium ion battery giving 8-10 hours of duty time.  Made in America

A jack on the Staff side of the unit for connecting
the battery charger, which requires a standard 110v wall outlet nearby.