Customer Reviews, including Product Star Ratings help customers to learn more about the product and decide whether it is the right product for them.
To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyzed reviews to verify trustworthiness.
I've got a 385 deadlift with a mixed grip with no problems (1 rep) and consider my grip moderately strong - rarely using straps and a couple years of rock climbing, and tested today at 110 lbs at the highest. This goes to 130 and then some (Probably 150 once you reach the top again), so for most people it's probably a great starter tool to see where you're at