This budget Gunson undercut every rival on price by a mile, and made clear its value for money credentials by giving 6V or 12V operation at the slide of a switch. It did well to charge when the test battery was showing only 6V. On the downside, it's heavy, has crocodile clips only, no warning lights and plugs directly to the mains. So, it's less versatile and needs to be close to the car, or used with an extension lead.