"Why so expensive?"
I wish I could sell my armor at a less expensive price, but carbon fiber is expensive, and there is a lot of labor involved. It's a one person operation, and it takes a lot of time. So this is what I have to sell it for to make it worthwhile. This armor adds a lot of frame protection at super low weight and it looks a lot better than an old tire zip-tied to your downtube. It will fit a variety of frames. If you have an expensive carbon fiber mountain bike, I believe that my armor is worth the investment to prevent frame replacement due to damage from flying rocks.
Clean your frame really well. I use alcohol for my final wipedown.
You might want to apply clear vinyl protective tape (especially over serial number) to frame before carbon armor if you want to remove the armor easily in the future.
Start at the bottom with a strip that is a hexagon in the center, with two half-hexagons on the outside.
Tape film is easiest to remove with an exacto knife or razor blade.
Apply armor with exposed tape and press hard for 30 to 60 seconds.
Alternate interlocking armor pieces and end with single hexagon at top for leading edge.