To calculate the overall star rating and percentage breakdown by star, we do not 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 analyses reviews to verify trustworthiness.
I have had these installed for over 8 yr and bought more for my new home. The easiest sliding door safety lock. I chose them again since I will be renting and they are easy to remove or cheap enough to leave behind.