I bought a “ Streetwize” emergency jumpstarter and powerbank. I’d not seen one, except in a video, and didn’t know what to expect. .but my car wouldn’t start. I couldn’t believe this little box would start my big old diesel. The case looked like it might contain a gift set of pens. It promised also to charge laptops and phones. Seemed unlikely to me. When I attached it to my battery it gave me a reading. When I turned the key, the car roared into life, after two weeks idle. Normally, when you buy something you know what it can do, but I was amazed with this little device. Starting my car made no impact on its power level and after a week it is still fully charged. I’ll have to try it on my laptop next. I’m very pleased with it. The service at Argos also was very good, from ordering it over the phone to the very pleasant assistant in the Chancery Lane branch.