I have had these for 2 years. https://www.amazon.com/Fitness-Insanity-Resistance-Band-Set/dp/B01GCA4BJC/ref=sr_1_13?s=exercise-and-fitness&ie=UTF8&qid=1550677953&sr=1-13&keywords=resistance+bands

I should note that I only use them when on the road as I have weights at home. They are strong substitute for pull ups as far as bands go, because you can combine several bands to really increase tension. However, they are a pain in the butt to use as weight substitutes because there is only one pair of handles that must be disconnected and connected every time you want to change the resistance band. I'd recommend spending more on a set that has permanent handles on every band. It will save you time and hassle.