Saddlebags are bags that you can put on a horse to carry things.
Saddlebags are useful for carrying things when you are riding a horse.
Examples:
The cowboy put his water bottle in the saddlebags.
The saddlebags were heavy with all the supplies.
She packed some snacks in the saddlebags for the long ride.
The saddlebags were so full, they looked like they might burst!
The saddlebags were as big as a house!
The horse wore saddlebags to carry the treasure.