Have been looking for about 6 months for a battery tender.. more specifically a 4 battery tender with great reviews. I had settled on a specific one and thought purchasing would be easy... then reality and out of stocks came to view .. INCLUDING THE MANUFACTURER! Other sites had these available.. at about a 150% mark up. Then I found RYSZ! They had 2 instock.. no markup, and a delivery promise that actually made it almost 2 days earlier! Could not be happier with this purchase and definately will be buying from RYSZ again! Thank you for everything!