Reliable vehicle jump starter

The winters are getting colder. I purchased a battery jump starter compact enough I carry it in my purse. No more membership fees and trying to flag someone down to jump start my car. Affordable at Walmart. So,having booster cables and my own jump starter I feel more comfortable on the road. You simply
Plug it in via USB and turn it off until your ready to use it. Comes with the power pack and USB. Energy efficiency.