Door popper stuff....

I just got my Dakota Digital door popper kit in the mail today and I just wanted to make sure I dont need anything else. I also wanted to find out what everybody uses for backups in case the door popper takes a shit or if something were to happen. I know there are kits out there for that but I cant remeber where...

Parts I have:Switch, 18" stainless cable and crimp fittings, 35lb solenoid, wiring connectors, bolts and mounting kit, fuse holder and fuse, and relay/remote system.

Is there anything else I need? Thanks in advance...Im pretty much sure this is fine what I have but just want to make sure...