Are you talking about the Gator belts?

There are a several different types of trizact belts. Not sure which ones you ordered, but they each have some pretty unique characteristics. Personally, I feel that any variety of trizact is best used on larger cross sections of material... like grinding the flats/bevels of a blade. I say that because in my experience if you grind thin/narrow cross sections (such a the spine or edges of a blade in line with the rotation of the belt, where you're only making a very narrow contact band, it tends to do what I call "gut" the belt...meaning that it takes out a narrow band of abrasive, which causes problems if you go back to larger cross sections on the same belt.

The trizacts that I do use, tend to be the finer grits....A30 an finer.

Karl, I believe they are gator belts.

Ed, I appreciate the answer and it makes sense to me. I ordered, A30,A45,A100 and A160. Figured a try the range.

I use the original (307EA) Trizact in A30 & A65, I prefer them to the newer belts (Trizact CF).

I've got a range from A300 down to A30. They last for a long time. However, one thing I've noticed over that time is that if you use them to routinely grind the spines of your knives, over time the belts loose their "flatness" so to speak. I find it much more difficult to get a good flat grind on them as I move to the higher grits. Maybe that's just me.

I just ordered a new batch, and I plan to only use them to grind the flats on my knives from here on out.

Another thing to remember about these structured abrasive belts is that they should be used at very slow speeds for optimal performance. I frequently use the A45 flat ones (not the Gators) rolled over the edge of the platen to put a beginning polish on my plunge cuts.