If you have a Kwikset Smart Key lock, this is the perfect solution for rekeying it. The kit comes with everything you need: the Smart Key tool, four new keys, plus two alternate keys, and easy and clear instructions. Rekeying took me about 30 seconds.
The only downside to the kit is getting it open. It's packaged in what seems like bullet-proof plastic. Be careful if you use a box knife to open it. It's tough. Opening the package took me at least five minutes, maybe ten.
A clearer way to describe the included keys is to say the kit includes one set of four keys and another set of two keys, allowing you to rekey your Smart Key lock twice (or change it back and forth). One suggestion is that you can use the two-key set (the "alternate" keys) to temporarily rekey the lock so that a repairman can have access to the house. After the repair or whatever is finished, you can rekey back to the other key set.
Finally, considering the cost of having keys made, buying a new lock cylinder, or hiring a locksmith, the price of this set is a bargain.
Caveat: You must have a Kwikset Smart Key lock to use this kit.