Raco
3-1/2" x 1-1/2" deep steel octagon box, 3 each 1/2" knockouts, use non-metallic sheathed cable clamps, 11.8 cuin.
Forney Industries Battery Jumper Cables
First Alert SCO501CN-3ST Wireless Interconnected Combo Smoke & CO Alarm w/ Voice Alerts
Gardner Bender WingGard Assorted Wire Connector
Dewalt 20v Max* 6ah Battery (2 pack)
GE Meter Socket Load Center (200A)