Literally, I screwed up. I got a set of detachable prop guards from SSE for my P3P. There were no directions. I figured out how they go on and opened a bag of screws and put a couple in. I realized there were way too many in the two bags, so I double checked them. One bag was for the P 2 and the other for the P3. Of course I was using the P2 ones. So I removed them and put in the screws from the P3 bag. When I get all done, I find one extra screw on the table. I count the P2 bag and it's one short. So, not knowing which bag the extra is out of, now I've got to start over to make sure I used all of the right screws. I'm aware that the wrong length screw, can damage the motors. My research confirmed that the P2 screws are longer than the P3, so I figure I'll take out each one and match it to one I know is from the P2 bag. Well, as far as I can determine visually, is that if they're different lengths, it's about a hair of being the same. So now I'm trying to figure out a foolproof (emphasis on fool) method to make sure I sort this out correctly before I power the bird up with the guards on.