Battle ropes are wonderful for core and cardio training. They do require a decent amount of space though. The Hyperwear Hyper Rope is a more compact solution that can still give you a good workout. It requires only 6 ft of space. You can perform a wide variety of exercises with it unanchored.
The Hyper Rope has a flexible metal core with 15lbs of resistance. It can be used indoors and outside. You can find out more about it here.