Best thing I ever bought was a Hive 1000cc wax heater, it has a lockable lid and has saved my wax from going everywhere on more than one occassion. I heat it up before I leave, pack everything else in the car and literally just as you are leaving, take it to the car with you and put it in your passenger foot well.
When you get to the clients house, take just the wax and maybe your small box of things you need. Ask is there anywhere you may plug your wax in and then do so. Then go back to the car, get whatever else you need. Set up, do consultation and by the time you have done all that and ready to use the wax it has warmed up again.
Just check the temperature dial when you plug it in at the clients house. I did all the above and when I went to use it, I hadnt realised I had knocked the temperature dial down. :cry: