Bad product. I bought it because Spigen no longer makes tempered glass for the 40mm Apple Watch (only Neoflex, which is also very bad and comes off very easily).
The orange plastic guide is bigger than the watch, the glass pieces are of low quality.
I put on the first one, full of bubbles that wouldn't go away no matter what. I tried very carefully without the guide, and still one bubble remained. Overall, I regret spending my money.