Let me start by saying that I only give 5 stars when they are really deserved. This is a charger that everyone who has expensive AGM, SLA batteries should have. Simple plug and play usage. Simply connect the supplied jumpers to the charger, connect the batteries to the + and - terminals and switch it on. Keeps your battery charged, charged, overhauled and even repaired in some cases. This charger can do what other standard car battery chargers cannot. If you have an expensive battery and don't want to change it prematurely, this is a MUST. CTEK generally makes great products in MHO! I am a professional mechanic and this product is used constantly in my workshop and has never let me down. I own several exotic foreign cars and the batteries I use start at $350 each. up to $1,350 each. If left uncharged or left idle for too long, they will run out of energy and cannot be restored or restored and will need to be replaced. If you have a Porsche, Audi R8, Bentley, Rolls-Royce, Mercedes, BMW, etc. you need one of these if the cars are worth more than a few weeks. Comes with a great little cable storage bag. Advantages: light weight, small size, portable, easy to use. easy to understand, the little colorful lights! You might save a few hundred dollars for just 1 expensive battery that you don't have to replace. It's worth it. Cons: I only have 1!