Our aftermarket stone guards have the option to add masking (default) or not. What is the difference?
Masking is the clear tape on top of the stone guard. It's what you hold on to when you're applying the stone guard, then peel off and throw away once it's on. An unmasked stone guard doesn't have that, it's just the clear stone guard on a waxy piece of paper.
With masking. Without masking.
So who would be crazy enough to prefer a stone guard without masking? We would! And here's why.
We prefer to install most of our stone guards wet, spraying a solution of soap and water on the sticky side, applying the stone guard and pushing out the water with a squeegee. The masking (either ours or the masking on OEM stone guards) creates problems with that.
First, you can't see what you're doing. Many times, we've put on a stone guard and pulled off the masking only to find out that the stone guard was crooked or misplaced. The second problem is that the masking traps water, sometimes making it impossible to get the water out and get the stone guard to fully adhere to the vehicle. And finally, sometimes when removing the masking, it will pull the stone guard off the vehicle, or pull up on it enough to create bubbles.
These problems aren't with the stone guard themselves, they're created by the masking, and we much prefer to use an unmasked stone guard to bypass all these problems.
When using an unmasked stone guard, our process is to:
Wash your hands. This is very important.
Carefully pull the backing away from one corner of the stone guard, preferably without touching the stone guard (this was done in the second photo).
Spray soapy water on that corner of the stone guard.
With clean hands, you can now touch the wet area and peel the stone guard the rest of the way off.
Wet the rest of the stone guard, place it on the vehicle, and squeegee out the water.
(optional) Instead of touching the stone guard, you can put a small piece of tape on the edge and hold on to the tape like you would hold on to the masking.
Our method may not be for everyone, but it works for us. We've installed a few thousand stone guards over the years and we pride ourselves in a perfect, bubble free fit. And after all that experience, we still occasionally get frustrated with masked stone guards, wad them up, throw them in the trash and go make one without masking.