1. Total lack of information
It's literally just a 3 ft tape measure. Nothing special. Had to go to the company website to find any info on it and they said it was the best tool out there for measuring sag and takes out the math. Got it and it's seriously just measuring tape. No special instructions for how to use it specially. Wtf! Worst 10 bucks I spent. I could have found a 2 dollar measuring tape that does the same thing