Brivo ACS6100 Large Expansion Chassis (Accommodates eight (8) ACS6100 expansion boards) Includes: (1) Large enclosure with lock (2) B-ACS6100-PSB internal power supply boards (does not support power for electronic locks) (2) Plug-in AC/DC power adapters (1) 12v 28Ah sealed lead acid battery backup (Compatible with all Brivo ACS6000/6100 series boards) *The B-ACS6100-PSB Can be used to replace an ACS6000 series power supply board.