When I travel I love to get in a great workout. It is great to travel with lightweight and effective equipment. I was really happy to test and review this product from PiJian: The Pinjian Home Gym Pedal Fitness Latex Tube Foot Elastic Exerciser.
It may remind you of some ancient artifacts sitting in your grandparents basement, the metal coiled spring kind, that looks akin to a torture device. But this new version is safer and compact, making it easy to transport with you to the gym, office, or for when you are traveling and need to get in a great workout. I like using mine for core work arms.
You can get yours at http://www.amazon.com/dp/B015IE4OP4.