I have various items from K&F Concept and I appreciate their products for good quality at an affordable price.

This set is a small bible of action camera vloggers. It's got a head strap, chest strap, wrist strap and a crocodile backpack clip. In addition you get a phone holder.
It comes in a nice carton box, although I wouldn't mind a small bag or a case for it. I have a larger set of budget accessories for action cameras that came in a really nice case.
Each part of the set is nicely made. The straps are quality, with anti-slip strips on the back side and easy to use adjusters. The actual mounts are made of decent, sturdy plastic. A bit of a shame it's glossy and so will get a lot of scratch marks after some use. I'd prefer a matte one, but it's just an aesthetical detail.
The head strap is comfortable to wear and comes with a rotating mount - you press the sides of it and you can rotate at set positions.
The wrist strap has the same mount and decent amount of padding. It's secured by a velcro strap.
The chest strap is the only one that hasn't got the rotating center - why? I don't know. It would have been useful for vertical shooting. Instead you get an adapter for that, which is only half joy as it won't let you change orientation ‘on the fly'.
The phone mount is quite standard. It has a connector that is compatible with action camera equipment. The inside of the mount is padded for protection of your mobile device and the clips are rubberized to hold the mobile firmly. At the back of the mount you also get a ¼” - 20 threaded hole if needed and a cold shoe mount at the top for fitting a light or a mic. It stretches on a spring mechanism to accommodate most mobiles out there.
Finally you get an adapter to connect anything that uses a standard ¼” - 20 screw.
The camera gets attached to each strap by a uniformed clip. It's easy to mount and dismount and it's also made of sturdy plastic. You get 4 of those with the set, as well as some typical action camera screws to secure the device to each strap.
The positives of this set are that all the items are lightweight and made of decent materials. Attaching components is quick and easy.
The negatives are more individual. The head strap and croc backpack clip are all good, no issues there. The wrist strap’s rotating mechanism feels a bit too stiff to use. I have another wrist strap with a securing ring, where it works a lot better. Finally the chest strap, apart from no rotating mechanism, may get a bit uncomfortable to use in time, as it has no padding on the inside, just the strap itself and the plastic. I have another chest strap with nice padding inside - way more comfortable. But other than that it's ok, even has a quick detach clasp.

The price of this set is £22. I think it's well balanced based on the quality of the items, especially the straps themselves. The carry/storage bag or box would have been really useful, but would probably boost the price higher. 4 stars from me as I'm happy to recommend this set despite the small snags.

Thank you for reading my review. I hope you found it helpful.