I ordered this at 10.20pm last night and the doorbell rings at about 10am this morning with the package – I think that's the fastest delivery I've ever had from Amazon, and this wasn't even sold by Amazon!
As for the product, I was encouraged by other reviews and was confident of a quality product – and that it certainly is. I bought the green one – it feels rugged and I can't find a join in the loop, which I thought would be a potential weak spot. Tied it onto my pull-up bar and tried it out and it's excellent. I would say the resistance stated is spot on (based on how pull-ups felt compared to a weighted assisted machine at the gym also set to 50kg). This is so much better than my previous set up with a step stool for assistance, as with that, there's no way of accurately gauging how must assistance I'm giving myself with my legs. With this, it's the same resistance on every rep – I could easily tell my legs have been giving me too much assistance up to now!
What I like about using the band is it allows for full range of motion and gives the most assistance exactly where I need it (at the start) and then makes you work really hard at the top end once it's nearly fully contracted. The intensity of my workout instantly increased and I can tell this will help with my progression to unassisted – probably quicker than the gym machine for the reason above!
Came with a card showing a bunch of other exercises you can do with it like squats and bicep curls. The resistance of the green band isn't right for me for those exercises, but I'll probably buy at least one lighter resistance band as the next step for pull-ups and to do some other exercises with.
Faultless service and a brilliant product – thank you!

Great value and really good quality. 85kg male doing chin ups with my knee in the bands, that’s a lot of stretch, and they cope with it easy

These bands are quality made, do the job consistently, minimal abrasion on the edges due to threading them over the bar, or wherever appended from.
I have one set, and now with a modification to my routine it's time for some additional bands to make a couple of matched pairs.
If you are going to spend money on bands, spend it on these.

I don't usually write reviews on Amazon, but I've been using these Iron Core Fitness bands for just over a year (purchased June 14 2021) and have been a happy user. However today, the second largest one (purple 40-80 lb) snapped while exercising with it. Fortunately I was wearing workout gloves so it didn't injure me, but just imagine doing anchored pulldowns, pulling the band toward your face, and having it snap on you… I'm a decently in shape guy, but I'm no Arnold Schwarzenegger, so it wasn't my heroic strength that broke the band. Unfortunately when one band in a set breaks, you're stuck as the bands all complement each other (as anyone who uses bands will know). They've been reliable until today, but I didn't think I was buying a set for just 1 year. So fair warning: if you're considering buying these, think of the price more as the "rental" price than the purchase price and you'll be making the right evaluation. I gave it two stars instead of just a single star because I did get a single year of use and not nothing.
UPDATE: I reached out to the company about the snapped band and I got a response within one day, asking for a picture of the snapped band and my shipping address so they could send a replacement. The next day (I live in a city) I had a replacement delivered in good working order. Based on that I am revising the rating up to 4 stars as any product can have failures (and this one did), but they stood by it and promptly fixed with minimal hassle. Based on this, I would buy from them again.

The band was needed to assist with an arm injury and to complete exercises from a physio. Perfect for the job needed

Peace of mind that it won’t snap and knock the coins out of you!
Good quality item, I’ve had them for some while now and they’re still as good as new!

Good

Unless I'm really missing something and I would love clarity… these seem way too short for assisted pull ups. Even when I'm stood on a bench they only come down to my chest and I'm quite tall (6'1).
They are of good quality and I can probably use them for other exercises, but I specifically bought these for pull ups, and the intended purpose doesn't seem to be there.