Manufacturer's refills cost almost as much as a new printer, so this kit saves a lot of money.
The kit allows you to refill the toner on a Samsung CLP-300, CLX-2160 or CLX-3160.
You don't get a lot of toner in the bottles (enough for one fill).
I found it a bit messy to do. Unlike an refilling an inkjet cartridge (where you only need to make a small hole for the liquid ink to enter) you have to have a large enough hole to permit the powder to go in. This means that you need a small funnel. You need to make a hole in the cartridge that is big enough to take it, and patience to slowly put the powder into the funnel so that it does not clog up.
Drilling a hole in each toner cartridge unit was not easy. You must not get any bits of plastic inside. If you do, you have to tip out the contents (messy). After doing the first I decided to heat a piece of copper pipe and use that to melt a hole in the plastic drum. This worked very well.
Afterwards you have to close the hole. Using tape is not as easy as it seems at first sight. The toner cartridges are a close fit in the printer, so the thickness is important.
Putting the new reset chips in was easy, but removing the old chips was not and I stuck the new ones on the old.
A good kit, but a pity they didn't include a means to make the hole and do the filling and then plug the hole.
Having said all of this, the result was every bit as good as the manufacturer's own product (apart from the taped up holes) and very much cheaper than the OEM product.
A point to note is that the original cartridges supplied with my printer did not have any chips in them.
When you have refilled your cartridges, it is a good idea to take out the waste toner container and empty it (don't buy a replacement).