I have a Pit Barrel Cooker that I use for grilling and smoking. The grate was always difficult to clean, and I was afraid of using the metal wire brushes as they tend to fall off and get into the food. So I bought these a while back, and it is an amazing product. When you open them up, they just look like a block. Once you start scraping the grate, the ridges start to form.
It has been about 6 months, and I have gone through one block. It does a great job.