TRX Bands are a commercially available suspension training device. You can purchase them and find out more information here
Here’s a video to check out this product.
Now, I’m not one who likes to spend $150 bucks on exercise equipment. So, I ventured into a local tool store and found these…

Web Sling
They’re a mere $9.99 and you can probably get them cheaper elsewhere. It’s about 6.5 foot and can handle up to 2000 lbs. I just hang it over a bar and loop one end through the other to secure it. The only downside is that it’s not adjustable like the TRX bands. But, with a little ingenuity, that’s not that difficult to overcome. You could fold up part of it and use some good ol’ duct tape to secure the folded section or just devise a way to wrap it around the bar a few times.
I’d much rather spend $20 versus $150. If you go on the TRX website, there’s a video library of exercises, too!